Wavelength-stabilized semiconductor laser diode for emitting continuous terahertz laser radiation, has plan-parallel plate made of optical transparent material, where plate does not have direct contact to emitted radiation

The diode has an arrangement of a semiconductor laser diode (7) and a plan-parallel plate i.e. etalon (4), made of optical transparent material, where the plate does not have a direct contact to a radiation (10) emitted from a laser exit surface. The thickness of the plan-parallel plate is chosen such that spectral spacing between two neighboring resonance wavelengths is larger than the spectral reinforcing bandwidth of the laser diode. Two surfaces of the plan-parallel plate form an angle with respect to each other, which is smaller than a divergence angle of the radiation.

Reduction of the noise from laser transmitters

In the case of laser transmitters, the laser noise can increase as a result of reflection to such an extent that the transmission is interfered with, particularly at high bit rates and with wide bandwidths. The invention proposes that the laser noise be minimised by setting a specific separation between the laser diode and the input optics or fibre ends, the minimising being achieved by means of a temperature change of the laser module. This is enabled in a simple manner by an actuating signal which is dependent on the laser noise being produced and by this signal being passed to the temperature regulator of the Peltier cooler contained in the laser module.

Laterales Maßschneidern einer Strominjektion für Laserdioden

Eine Halbleiterlaserdiode beinhaltet mehrere Schichten, die entlang einer ersten Richtung gestapelt sind, wobei die mehreren Schichten Folgendes beinhalten: eine erste Mehrzahl von Halbleiterschichten, einen optischen Wellenleiter auf die erste Mehrzahl von Halbleiterschichten, wobei der optische Wellenleiter ein aktives Halbleitergebiet zum Erzeugen von Laserlicht beinhaltet und wobei der optische Wellenleiter eine Resonanzkavität mit einer optischen Achse definiert; und die zweite Mehrzahl von Halbleiterschichten auf dem optischen Wellenleitergebiet, wobei ein Spezifischer-Widerstand-Profil wenigstens einer Schicht der mehreren Schichten graduell zwischen einem maximalen spezifischen Widerstand und einem minimalen spezifischen Widerstand entlang einer zweiten Richtung variiert, die sich orthogonal zu der ersten Richtung erstreckt, wobei eine Entfernung zwischen dem maximalen spezifischen Widerstand und dem minimalen spezifischen Widerstand größer als etwa 2 Mikrometer ist.

Optische Sender

Optischer Verstärker mit verbesserter Linearität

Steuerungsvorrichtung für Halbleiterlaser zur Stabilisierung der optischen Ausstrahlung desselben

Verfahren und Vorrichtung zum Betreiben einer Laserlichtquelle

Verfahren zum Betreiben einer Laserlichtquelle (10a) aufweisend die Schritte: a) Zyklisches Ermitteln eines elektrischen Spannungsabfalls an der Laserlichtquelle (10a) durch Bestromen der Laserlichtquelle (10a); b) Zyklisches Ermitteln einer Temperatur der Laserlichtquelle (10a) aus dem ermittelten elektrischen Spannungsabfall mittels eines vorab ermittelten ersten mathematischen Zusammenhangs aus elektrischer Spannung und Temperatur der Laserlichtquelle (10a); c) Ermitteln eines Stroms, der bei jedem ermittelten Temperaturwert eine im Wesentlichen konstante optische Ausgangsleistung der Laserlichtquelle (10a) bewirkt, mittels eines zweiten mathematischen Zusammenhangs aus optischer Ausgangsleistung und Strom; und d) Bestromen der Laserlichtquelle (10a) mit diesem Strom.

Vielfachlaseranordnung.

Treiberstufe für Halbleiterlaser

Method for determining and regulating the temperature of laser diodes, and a circuit arrangement for carrying out the method

A method for determining and regulating the temperature of laser diodes and a circuit arrangement for carrying out the method, the laser diodes being used especially in line printers and being operated in the pulsed mode. The essence of the method according to the invention is that a constant basic current, which is lower than the laser threshold current, is passed via the laser diode at the time interval at which emission of the laser radiation is suspended, during which the voltage of the laser diode is sampled at least once, and after which the sampled value is stored and evaluated, and the current supplying the laser diode is controlled as a function of the result obtained. The essence of the circuit arrangement according to the invention is that the connections of the laser diode are connected to a sample and hold unit via a voltage follower having a high input impedance, the output from which sample and hold unit is passed to an evaluation unit, while one output of the evaluation ...

TEMPERATURREGELUNG FÜR EINE LASERDIODE IN EINEM PLATTENLAUFWERK

Fehlertolerante Diodenlasereinheit

VORRICHTUNG ZUM MODULIEREN DES AUSGANGS EINES HALBLEITERLASERS

AUTOMATISCHE VORSPANNUNGSSTEUERSCHALTUNG FUER INJEKTIONSLASER

Laser systems

Output pulse width control system

LASER DIODE INTENSITY AND WAVELENGTH CONTROL

Control and calibration of laser systems

A light emitting semi-conductor device having current overload protection

A light emitting semi-conductive device 15 is mounted on an auxiliary semi-conductor chip 25 which acts both as an overload protection resistor 26 as well as a heat transfer member. The heat transfer member is thus integrated with the drive protection resistor of the light emitting device. A principle heat-sink 17 is mounted on main frame within a package and is coupled to the light emitting semi-conductor device 15. The auxiliary semi-conductor chip 25 is connected with both the heat sink and the light emitting device and has semi-conductive regions 26 defining the protective resistor electrically coupled with the light emitting device. The invention avoids the use of discrete resistors and substantially reduces the assembly processes of soldering and bonding to a printed circuit board. The device may be used in fibre optic communication.

A high power diode laser and method for mounting such a laser

FREQUENCY REFERENCING SYSTEM

LIGHT EMITTING DEVICE

Laser driver control circuit

Optical fibre amplifier

In an optical fibre amplifier in which a doped optical fibre 7 is pumped by a redundant arrangement of two coherent light sources 1,2 such as laser diodes, the output of the light sources being coupled to the fibre by a coupler 4 and a wavelength multiplexer 5,6, at least one reflector 15,16 is used to prevent injection locking of the two sources and thus variation in the gain of the fibre. As shown, there are two reflectors located between the coupler 4 and respective light sources 1,2, each reflector having a reflectance peak at a different wavelength. The wavelengths of the light sources are thereby locked to the wavelengths of the reflectance peaks. Alternatively, the reflectors may be located between the coupler 4 and respective wavelength multiplexers 5,6 or between the coupler and one of the wavelength multiplexers. If the two sources emit light with different polarisation states, a single reflector having a reflectance peak which varies with polarisation may be used. Alternative ...

Light amplifier

OPTICAL RADIATION GENERATOR ELECTRICALLY CONTROLLED

... 1506750 Optical generator with feedback THOMSON-CSF 4 July 1975 [5 July 1974] 28376/75 Heading G1A Such a generator controlled by a current has two terminals 3, 10 for this current connected to current amplifier A, with its output connected to L.E.D. L with a radiating surface close to and optically coupled by a transparent medium M to an end of an optical fibre F and to photodiode P connected to the input of amplifier A 2 , with its output connected to the input of A 1 . GaAs L.E.D. L and photodiode P which is a junction on a silicon substrate, are attached by electrically conductive weld layers to conducting substrate S. In the embodiment of Fig. 2 (not shown) the amplifiers are outside the substrate S. In that of Fig. 3 the amplifiers A 1 A 2 and photodiode P, are an integrated circuit on a silicon base. In the embodiment of Fig. 4 (not shown), the diode P and fibre F face opposite polished ends of laser diode (L 1 ).

Discharge lamp.

A digitally modulated injection laser is provided with a control circuit to keep constant both its "zero" and "one" light output values despite changes in duty cycle and aging effects. The circuit includes one branch which maintains constant the average light value and another branch which maintains constant the difference between the "one" value and the average light value.

MAINTAIN A DESIRED EFFICIENCY OF OPTICAL EMITTERS WITH EXTREMES TEMPERATURES

LASER SYSTEM WITH EXTERNAL OPTICAL FEEDBACK AND USE OF SUCH A SYSTEM IN THE GRAPHICS INDUSTRY

PROCEDURE AND MECHANISMS FOR THE EDUCATION OF A COHERENT HIGH SPEED RAY OF LIGHT

ATHERMALISIERUNG TUNABLE LASER

AUTOMATIC RULE SWITCHING CONFIGURATION FOR REGULATING THE PERFORMANCE OF A DIGITAL TRANSMITTER

PROCEDURE FOR THE CONFIGURATION OF A LASER OPERATING SYSTEM

LASER DRIVER WITH SEVERAL FEEDBACK LOOPS.

MONITORING AND CONTROLLING OF THE STABILITY OF A RADIATION SOURCE.

MONOLITHICALLY INTEGRATED CIRCUIT FOR REGULATING THE LIGHT ACHIEVEMENT OF A LASER DIODE

Wavelength stabilization

METHOD FOR CONFIGURING A LASER OPERATING SYSTEM

MAINTAINING DESIRABLE PERFORMANCE OF OPTICAL EMITTERS AT EXTREME TEMPERATURES

Laser optics integrated control system and method of operation

LASER DEVICE

Gain voltage control of sampled grating distributed bragg reflector lasers

TECHNIQUES FOR BIASING LASERS

Laser drive circuit

A LASER DIODE TRANSMITTER WITH A PROTECTIVE CIRCUIT

Automatic compensation of cnr and omi in a laser transmitter

Intelligent fiberoptic transmitters and methods of operating and manufacturing the same

Optical communication system

SEMICONDUCTOR LASER DRIVING DEVICE AND IMAGE FORMING APPARATUS HAVING THE SEMICONDUCTOR LASER DRIVING DEVICE

A semiconductor laser driving device that drives a semiconductor laser with a driving current output from a driving current output terminal is disclosed. The semiconductor laser driving device includes a driving current monitoring terminal configured to output a driving current monitoring current having a value of 1/a of the driving current; a current-voltage conversion resistor connected to the driving current monitoring terminal and configured to convert the driving current monitoring current having the value of 1/a of the driving current into a corresponding driving current monitoring voltage; and a detector configured to generate a reference voltage and detect whether the corresponding driving current monitoring voltage has reached the reference voltage.

SEMICONDUCTOR LASER DRIVING DEVICE FOR STABILIZING THE OPTICAL OUTPUT THEREOF

In a laser driving device for stabilizing the optical output level of a semiconductor laser, a drive circuit supplies a drive current signal to the laser. A monitoring photodiode is provided for partially receiving the optical laser output to produce an electrical monitor signal indicative of the actual output level of the laser. A differential amplifier is connected to the photodiode to serve as a comparator for receiving a reference signal indicative of a reference output level of the laser, and for detecting a difference between values of the monitor signal and the reference signal to produce a comparison signal indicative of a change in the actual optical output level of the laser. An abnormal current eliminator is connected to the comparator, for, when the laser is disenergized or just after it is driven to become operative, controlling the comparator so that the comparison signal has a limited amplitude, whereby a current component undesirably supplied as the driven current to the ...

POWER SUPPLY SYSTEM FOR A SEMICONDUCTOR LIGHT SOURCE

LASER DIODE DRIVE SYSTEM

A laser diode drive system for generating a drive current for a laser diode is described. The laser diode drive system comprises a first laser diode driver connected to the laser diode by a first cable to provide a drive current source for the laser diode. A second laser diode driver is then connected to the laser diode by a second cable to provide a low current sink for the laser diode. A feedback control loop is employed to provide a feedback signal for the second laser diode driver from to sample of an output field of the laser diode. The laser diode drive system exhibits low power consumption while being capable of creating sufficient feedback bandwidth to reduce the excess optical noise by at least an order of magnitude at 1 MHz compared with laser diode drive systems comprising just a first laser diode driver.

FIBER GRATING FEEDBACK STABILIZATION OF BROAD AREA LASER DIODE

The laser device of the present invention includes a high-power, fiber-coupled optical source having a broad area laser diode (10) with a high reflective coating at its rear facet (12), coupling optics (20), and an optical fiber (30) having fiber grating (32). The fiber grating (32) serves to reflect a portion of the optical beam back to the broad area laser diode (10), thereby stabilizing the wavelength of the optical beam. The fiber grating (32) and the rear facet (12) of the broad area laser diode (10) serve as nodes for an external resonator, thereby limiting the diffraction of the optical beam. The effects of wavelength fluctuation and beam diffraction are reduced together using minimal mechanical components.

SYSTEM AND METHOD FOR CONTROLLING COLLOCATED MULTIPLE WAVELENGTH TUNED LASERS

Systems and methods are disclosed herein for controlling laser beams for a plurality of collocated laser assemblies. The laser beams are optimized by controlling outputs of a primary power source (current for generating a laser beam) and a secondary power source (heating device) for each of the respective laser assemblies. The states of the power supply may be cycled and modulated to provide optimal performance.

SYSTEM AND METHOD FOR GENERATING LIGHT PULSES BASED ON DIRECT CURRENT MODULATION OF A SEED LASER DIODE

Laser pulse generating systems and methods are provided. Using the modulation signal from a pulse generation module, a seed laser diode generates seed light pulses in response to direct drive current modulation. The seed light pulses having a pulse duration longer than a target pulse duration and a spectral chirp. A compression module having dispersion characteristics over a broad spectral range is provided. The pulse generation module is configured to adapt the modulation signal to tailor the spectral chirp of the seed light pulses in view of the dispersion characteristics of the compression module, such that propagation of the seed light pulses through the compression module compresses the seed pulses into output light pulses having the target pulse duration.

RAPID TURN-ON SOURCE FOR FIBER OPTIC GYROSCOPE

A light source with wavelength compensation for a fiber optic rotation senso r includes a light source to provide light for input to the fiber optic rotation sensor. A source control circuit generates a source con trol signal representative of the temperature of the lig ht source. A driver generates a drive signal as a function of the source control signal to drive the light source. One of a plurality of scale factors for the fiber optic rotation sensor is generated also as a function of the s ource control signal over a predetermined temperature ra nge. The source control circuit includes a temperature sensor which provides a curren t signal representative of the temperature of the light source and a buffer network for sinking the current signal and for generating a sou rce control voltage as the source control signal. A meth od for wavelength compensation of a light source for a fiber optic rotation sensor includes sensing a temperature of the light source and g enerating a source control ...

METHOD OF OPERATING A SEMICONDUCTOR LASER AS A MODE-LOCKED SEMICONDUCTOR LASER AND DEVICES FOR IMPLEMENTING THE METHOD

A semiconductor laser (1) is known that is monolithically integrated on a substrate (2) and whose cavity (41) has a branched structure that is simply contiguous in a topological sense. The semiconductor laser (1) includes a plurality of regions (8-11) that enclose the cavity (41). According to the invention, the semiconductor laser (1) is operated as a mode-locked semiconductor laser, with an alternating current flowing through at least one region in addition to a direct current. The frequency of the alternating current corresponds to the reciprocal of the round-trip time or an integral multiple of this reciprocal of the light pulses generated by the alternating current in the semiconductor laser (1).

WAVELENGTH MONITORING AND CONTROL ASSEMBLY FOR WDM OPTICAL TRANSMISSION SYSTEMS

A compact wavelength monitoring and control assembly for a laser emission source is provided comprising a narrow bandpass, wavelength selective transmission filter. element, of Fabry-Perot etalon structure, through which a non-collimated beam-from the laser source is directed onto two closely spaced photodetectors. For wavelength, stabilization, the differential output of the two photodetectors is used in a feedback loop to stabilize the wavelength of the laser source to a desired target wavelength. Through the angular dependence of the wavelength transmission of the Fabry-Perot etalon, a wavelength variation from the source is converted to a transmission loss, which is different for the two photodetectors, so that the wavelength change is detected as a differential power change. The device functions as an optical wavelength discriminator in which the detector converts optical energy to current for a feedback loop for controlling the light source. A lens may be used to control the divergence ...

HIGH-POWER DIODE LASER AND METHOD FOR MOUNTING THE SAME

The invention is directed to a high-power diode laser and to a method for mounting same. It is substantial to the invention to provide predetermined breaking locations in the laser bar which, during cooling after the laser bar ha s been soldered to a heat sink having a smaller thermal expansion coefficient, lead to breakage at defined locations between the single laser diodes of the laser bar. As a result of the physical division of the laser bar, it is possible to use a solder which has low ductility (hard solder) at room temperature, since destruction of the si ngle laser diodes of the laser bar as a result of mechanical stresses can be ruled ou t.

DRIVE CIRCUIT FOR A SOLID STATE OPTICAL EMITTER DEVICE

The present invention relates to a circuit for driving a solid state optical emitter device such as a laser diode, and in particular a circuit which limits the maximum current which may be drawn through the device. The circuit comprises a current supply path and a current return path to which the optical emitter may be connected, and current limit means (20) to limit a maximum current (Imax) that may flow through one of the current paths. The current limit means (20) has a current mirror with an input portion (21) and an output portion (23), the circuit being arranged so that when a first current (I R) flows through the input portion (21) the second portion (23) is predisposed to supply a second current (I O) up to a maximum which mirrors the first current (I R). The maximum current (Imax) through the paths is thereby limited in accordance with the maximum of the second current (I O).

CIRCUIT IN CMOS TECHNOLOGY FOR HIGH SPEED DRIVING OF OPTICAL SOURCES

A high speed drive circuit for optical sources. The circuit comprises bias and modulation current generators for both p-type and n-type optical sources, and a pair of control voltage sources for controlling the bias and modulation current generators, which obtain pairs of control voltages from an adjustable driving current. The circuit includes control logic and CMOS gates for selecting between the p-type and n-type generators by means of an external signal. The circuit is fabricated as an integrated circuit having three pads, one for each control voltage source and the third pad comprises the current generators, the CMOS gates and the control logic circuit.

CURRENT CONTROL FOR AN ANALOG OPTICAL LINK

A control circuit for an injection laser provides a pre-bias current which prevents clipping induced errors in the laser output. An analog modulating signal is provided directly to the laser which receives the sum of a feedback current (Ifb) and a current source (Io) as the pre-bias current (Ipb). A monitor diode detects the laser light output and provides a current (Idet). A feedback circuit operates in a limited dynamic range, e.g. I~ +/- 40 mA or is incapable of outputting a negative current (Ifb>0). The feedback circuit responds to changes in Idet and adjusts the laser pre-bias current to hold Idet equal to a preset value, which effectively holds the laser's average output power constant. If the pre-bias current necessary to hold Idet fixed falls below some minimum level, Imin, the feedback circuit will run out of dynamic range and the laser's average power will increase. By preventing Ipb from falling below Imin clipping induced errors and distortion are avoided.

LASER DRIVE CIRCUIT

A laser diode (1) is driven by a first, integrating, amplifier (5) receiving a d.c. reference voltage Vref, input data Vin, and negative feedback from a backfacet photodiode (2), and by a second, wideband, amplifier receiving the data and the negative feedback.

TUNABLE EXTERNAL CAVITY DIODE LASER

An external cavity laser system composed of a semiconductor diode laser (10), a temperature control (30) and injection current control (40) means the diode laser, an external cavity (60) with a wavelength selector and means for controlling the laser temperature (20), laser injection current and the wavelength selector (110) to obtain arbitrary frequencies within the tuning range of the laser.

LASER OSCILLATION WAVELENGTH MONITORING DEVICE

A laser oscillation wavelength monitoring device, which can obtain a changing direction and a changing amount of an oscillation wavelength without any relation with a polarization state of an incident light, whose manufacturing is made to be easy, is provided. The laser oscillation wavelength monitoring device provides a lens that converts an incident light from an optical fiber in which an optical signal is transmitted by a wavelength division multiplex (WDM) technology to a beam, a polarizer that makes an arbitrary linear polarization state in the beam transmit, a polarization splitting means that splits the arbitrary linear polarization state into a first polarization state and a second polarization state, a first and a second optical band pass filters to which each polarization state split by the polarization splitting means is inputted, a first and a second light receiving elements which receive light transmitted through the first and second optical band pass filters respectively and ...

METHOD AND APPARATUS FOR ACTIVE NUMERIC TEMPERATURE COMPENSATION OF AN ETALON IN A WAVELENGTH STABILIZED LASER

A unique method and apparatus for locking on an absolute wavelength of las er light output by a laser package by actively compensating for a change in the temperature of an etalon optical fitter is disclosed. Changes in etalon response characteristics due to temperature changes are compensated for by the addition (or subtraction) of an output voltage offset to the voltage control signal sent to the Thermo-Electric Cooler (TEC) from a controller within the laser package. The voltage offset is calculated by monitoring the etalon temperature. The voltage offset value provides for active compensation of changes in the etalon temperature and effectively "readjusts " the output of the laser as if the etalon temperature itself had been readjusted. ...

Anordnung zur Erzeugung rauscharmer Laser-Strahlung von elektrisch angeregten Festkörper-Lasern

PROCEDURE AND EQUIPMENT OF AUTOMATIC CONTROL IN NEGATIVE REACTION OF A DEVICE FOR THE TRANSMISSION OF DATA.

Laser and laser signal output method

Driving circuit and optical module with same

Stable light source device for multi-wavelength semiconductor laser communication

Integrated memory controller circuit for fiber optics transceiver

SAFETY DEVICE Of a LASER DIODE

DEVICE OF STABILIZATION OF the OPTICAL POWER Of a SEMICONDUCTOR LASER

PROCESS AND INSPECTING DEVICE OF the OPTICAL POWER Of a LASER TRANSMITTER

LASER DIODE HIGH POWER AND PROCEEDED FOR ITS ASSEMBLY

DISPOSITIF DE PROTECTION D'UNE DIODE LASER

LE DISPOSITIF DE PROTECTION D'UNE DIODE LASER 1 ALIMENTEE PAR LA SUPERPOSITION D'UN COURANT CONTINU DE POLARISATION I ET D'UN COURANT VARIABLE PORTEUR D'INFORMATIONSDI, A TRAVERS UN SYSTEME DE CONTRE-REACTION OPTOELECTRONIQUE 2 ET 3 COMPORTE UNE RESISTANCE VARIABLE 10 CONNECTEE EN AMONT DE LA DIODE LASER 1 ET DU SYSTEME DE CONTRE-REACTION 2 ET 3 DE MANIERE A FORMER UNE BOUCLE FERMEE AVEC LA SOURCE 8 DE COURANT PORTEUR D'INFORMATIONSDI, ET DESTINE A S'ASSURER DE LA POLARISATION DE LA DIODE LASER AVANT TOUTE INJECTION DE COURANT PORTEUR D'INFORMATIONS DANS CETTE DIODE. APPLICATION AUX SYSTEMES VIDEODISQUES.

CIRCUIT LIMITING DEVICE FOR LASER HAS SEMICONDUCTOR

UNCOOLED OPTICAL COMMUNICATION MODULE

SEMICONDUCTOR LASER APPARATUS AND PUMPING CIRCUIT FOR THE SAME

PURPOSE: A pumping circuit for a semiconductor laser is provided to prevent overheating of a semiconductor laser with simple structure and small size. CONSTITUTION: A pumping circuit for a semiconductor laser is coupled with a positive temperature coefficient (PTC) thermistor in series. The PTC thermistor has temperature coefficients -0.5%/°C to -1.5%/°C in temperatures -20°C to +70°C. The temperature coefficients are converted to positive coefficients in temperature over +70°C. A resistor insensitive to the temperature can be coupled to the PTC thermistor serially or parallel. The semiconductor laser and the PTC thermistor are approached sufficiently to form a thermal connection in a container such as a can forming a semiconductor device. COPYRIGHT 2000 KIPO ...

UNCOOLED OPTICAL COMMUNICATION MODULE

PURPOSE: An uncooled optical communication module is provided to reduce the volume and the manufacturing cost by installing a semiconductor chip on an upper surface of a thermistor having a positive temperature coefficient. CONSTITUTION: An uncooled optical communication module includes a plate-shaped thermistor, a semiconductor chip, and a driver. The plate-shaped thermistor(320) includes a positive temperature coefficient. According to the positive temperature coefficient, a resistance is proportional to the peripheral temperature. The semiconductor chip(350) is installed on an upper surface of the thermistor. The driver is used for applying the predetermined voltage to the thermistor. © KIPO 2004 ...

METHOD FOR CONTROLLING POWER IN OPTICAL DISC DEVICE

The present invention relates to a method for controlling power in an optical disc device. The method for controlling power according to an embodiment of the present invention comprises the steps of: measuring the RF level of a signal reflected from an optical disc by driving a laser diode with each of two or more drive values; calculating offset corresponding to a drive value when the laser diode starts to emit light, based on the drive value and the RF level; and compensating for the function of laser diode drive values for outputting target power depending on temperature by using the calculated offset. The RF level can be measured when a beam emitted from an optical pick-up focuses on the surface of the optical disc, and the RF level can be measured when the optical disc is loaded on the optical disc device. Therefore, the power of laser can be maintained constantly without using a part for measuring the output power of the laser diode, and the power of laser can be controlled more accurately ...

TEMPERATURE SENSOR, LASER CIRCUIT, LIGHT DETECTION AND RANGING SYSTEM AND METHOD

In one embodiment a temperature sensor has a first sensing unit (20) operable to provide a first pseudo-differential unipolar analog signal (31) representing a first temperature value of a power unit (19), an interface circuit (21) operable to provide a second pseudo-differential unipolar analog signal (32) representing a second temperature value of a powered unit (22), a multiplexer circuit (23) which is operable to provide a pseudo-differential unipolar multiplexed analog signal (33) comprising the first analog signal (31) or the second analog signal (32), and a first analog-to-digital converter (ADC) component (24) operable to provide a first digital signal (34) from the multiplexed analog signal (33), the first digital signal (34) comprising a digital representation of the first analog signal (31) or the second analog signal (32). Therein, the operation of the first ADC component (24) is synchronized with a control signal (30) designed for activating the power unit (19).

SELF-HEATING MITIGATION IN AN ACOUSTICALLY TUNABLE DISTRIBUTED FEEDBACK LASER

This application relates to a laser assembly displaying self-heating mitigation. The. laser assembly (100; 200) comprises: a semiconductor laser (110) with an active semiconductor region for emitting an optical signal in response to a drive current that is applied to the active semiconductor region, a drive circuit (120) for generating the drive current in accordance with an input signal and applying the drive current to the active semiconductor region, a controllable oscillator (140) for generating a periodic electric signal that is applied to the semiconductor laser (110) to generate a surface acoustic wave in or near the active semiconductor region such that a diffraction grating structure is created in or near the active semiconductor region by the surface acoustic wave, an emission wavelength of the active semiconductor region being determined by a periodicity of the diffraction grating structure, wherein the controllable oscillator (140) is configured to set a frequency of the periodic ...

PULSE LASER DEVICE

This pulse laser device is provided with: a semiconductor laser element that outputs a single-wavelength laser beam; a semiconductor optical amplifier, which receives the laser beam outputted from the semiconductor laser element, and amplifies and outputs the laser beam; and a semiconductor optical amplifier drive unit that supplies the semiconductor optical amplifier with a pulse-modulated drive current. Preferably, the pulse laser device is provided with a control unit, which has a semiconductor laser element drive unit that supplies the semiconductor laser element with a pulse-modulated semiconductor laser element drive current, and which also has the semiconductor optical amplifier drive unit, said control unit synchronizing pulse modulation of the semiconductor laser element drive current and pulse modulation of the semiconductor optical amplifier drive current with each other.

DIODE LASER DEVICE WITH COOLING SYSTEM AND SYSTEMS FUNCTIONS MONITORING SYSTEM

The invention relates to a diode laser device comprising at least one laser diode (14), a power supply (54) for said laser diode (14), a cooling system (76) with a cooling aggregate (20) on which the laser diode (14) is disposed, and a coolant supply (66, 68, 70, 72, 74) that allows a coolant to flow through the cooling aggregate (20). The aim of the invention is to improve such a diode laser device in such a manner that it is possible to carry out a monitoring of the system functions (80) in a simple manner and without impairing the utilization of the diode laser device. To this end, a systems functions monitoring system (80) is provided and said systems functions monitoring system (80) detects a variable (I) representing the electric current flowing through the laser diode and a variable (TR) representing the temperature of the coolant emitted by the cooling aggregate (20), and on the basis thereof determines a functional variable (F) representing the function of the diode laser device ...

PROCESS AND CIRCUIT FOR CORRECTING THE LIGHT-POWER OUTPUT OF A LASER DIODE

The invention concerns a process and circuit for correcting the light-power output of a laser diode. The circuit comprises a generator (2) for generating a driver current (IT) which determines the light-power output of the laser diode (1). The driver current (IT) is modulated by a modulation signal (B). To correct the light-power output, the circuit includes a linear low-pass filter (5) which is acted on by the modulation signal (B) and which approximately simulates the change with time of the internal temperature of the laser diode (1) as a function of the modulation signal (B). The output signal of the linear low-pass filter (5) acts as a driver-current (IT) correction signal (K), thus compensating for the temperature dependence of the laser-diode light-power output.

PRECISION TEMPERATURE SENSOR

A precision temperature sensor (10) is set forth. The sensor is a photosensitive device (12). Variations in temperature of the light sensitive device (12) cause changes in the voltage across the light sensitive device (12). The voltage can be measured in microvolts corresponding to fractions of a degree change, and is linear with change in temperature.

ATHERMALISATION OF TUNEABLE LASERS

This invention describes a technique and apparatus to use any tuneable laser to generate a specified output frequency without controlling its temperature. This technique only involves a thermal sensor and a controller to determine the current(s) or voltage(s) applied to the grating or tuning section(s) to obtain the required wavelength. The control loop can be implemented using a programmed microprocessor, an amplifier and a low pass filter.

OPTICAL TRANSMITTER

There is provided an optical transmitter capable of suppressing degradation in the distortion characteristics and RIN characteristics attributed to relaxation oscillation under high temperature by controlling the average driving current of such a light emitting element that the average optical output power from the light emitting element increases as the temperature, e.g. the ambient temperature of the light emitting element, increases.

METHOD AND DEVICE FOR OPERATING A LASER DIODE

The invention concerns a method of operating a laser diode (2) producing a beam (9) whose intensity is controlled by a control signal and which is directed along a first beam path (10) at the target surface (5), stray reflections from the target surface (5) which are unstable with respect to the diode (2) in time and/or space acting on the diode (2). An element (19, 28, 31, 37, 38) which is stable in time and with respect to the diode (2) in space is used to feed part of the light emitted by the diode back along a second beam path (11) to the active zone (42) of the diode (2) so that the diode (2) is kept in a state of coherence collapse.

SEMICONDUCTOR OPTICAL SOURCE CAPABLE OF COMPENSATING FOR TEMPERATURE-INDUCED VARIATION OF LASER OSCILLATION THRESHOLD

A semiconductor optical source includes a first laser diode (1) supplied with a signal current pulse and a first bias current for producing an output optical signal pulse in response to the signal current pulse, a first biasing circuit (4) for supplying the first bias current to the first laser diode, a second laser diode (2) supplied with a second bias current for producing an output optical beam in response thereto, a second biasing circuit for supplying the second bias current to the first laser diode; a heat sink for maintaining the first laser diode and the second laser diode at a substantially identical temperature; and a threshold detection circuit (3) for detecting a threshold of laser oscillation of the second laser diode, wherein the threshold detection circuit controls the first biasing circuit such that the first bias current is maintained at a level that is related to the threshold of the second laser diode.

LASER DRIVER WITH PLURAL FEEDBACK LOOPS

A laser driver circuit applies pulses of current to a laser diode (10) to activate the diode to emit pulses of radiation suitable for operation of a laser printer (16). A field-effect transistor (12) (FET) is serially connected with the laser diode (10) and with a feedback resistor (32) for applying the current pulses, the feedback resistor (32) serving as a source of a feedback signal indicative of the magnitude of current flow. A photodetector (54) senses radiation outputted by the laser diode (10) and emits an optical feedback signal representative of radiated power of the laser diode. A combiner circuit (40) responsive to an input digital command signal, combines the current feedback signal and the optical feedback signal with the command signal to generate a drive signal for activating the FET (12). The combiner circuit (40) includes an input section in which a current source powers a differential amplifier operating in a switching mode in response to the command signal, a driver section ...

METHOD AND APPARATUS FOR CONTROLLING EXTERNAL CAVITY LASER

Provided herein are a method and apparatus for controlling the wavelength of an external-cavity wavelength-tunable laser. The reflectivity or transmittance characteristics of a wavelength depend on the phase difference between light reflected by a wavelength-tunable filter and parasitic reflective light. Thus, when the temperature of a module and current applied to a phase control electrode and an external reflector are changed, the characteristics are changed in a periodic manner. The present disclosure relates to a wavelength control algorithm of determining combinations of these parameters to set conditions having optimum chirping characteristics at a desired wavelength.

Laser diode control apparatus

Control of the amplitude of data modulation applied to a laser diode is critical to prevent excessive wavelength shift and resultant dispersion of the signal in the waveguide at high data rates. The present invention utilizes the intermodulation products of two low frequency signals superimposed upon the modulation signal to produce detected products which are separated into appropriate components and utilized to control the amplitude of the modulation signal such that its logic 0 level occurs at a given optimum point. A further complementary and interacting control loop is utilized to control the bias point or center point for this data modulation signal.

Circuit arrangement for limiting the power of the optical signal emitted by a laser diode

In a circuit arrangement for limiting the power of the optical signal emitted by a laser, the current through the laser is supplied via a parallel connection of a plurality of series circuits of a transistor with a resistor. In addition, provision is made for a limitation, depending on the operating temperature of the laser, of the maximum current through the laser, which is realized by means of a temperature-dependent control signal fed to the control electrodes of the transistors.

Data reproducing apparatus using idling current

A data reproducing apparatus is disclosed which permits stabilization of the light output of a light source, thereby to permit reliable reproduction of data. When recording data on an optical disk and also when reproducing the recorded data by illuminating the optical disk by means of a laser beam from a semiconductor laser, an idling current is supplied in advance to the semiconductor laser, to such an extent that the semiconductor laser does not emit a laser beam. As a result of the preliminary supply of the idling current, the output of the semiconductor laser is stabilized.

Regulator for bias current of semiconductor laser diode

Current regulator circuits using electrical feedback to stabilize the bias currents of semiconductor laser diodes are disclosed. In these electrical feedback circuits laser diode current is sensed with negative-temperature-coefficient resistance to develop voltages which are compared to zero-temperature-coefficient voltages for generating error signals, and these error signals regulate the emission from the laser diode against changes with temperature.

Laser light control circuit, optical pickup unit and optical pickup device incorporating the same

A laser light control circuit with low power consumption and a small amount of heat generation by superposing a control current output from a light quantity control circuit with a high-frequency current output from a high frequency current generator on the basis of the control current, includes a bias circuit which sets a bias current of the high-frequency current in response to the operation voltage of a semiconductor laser element.

Apparatus and circuitry for stabilizing laser diode output for analog modulation

Circuitry and apparatus for stabilizing the output of a laser diode when modulated with a wideband analog signal. The circuitry provides for continuous operation of the laser diode with a pin diode positioned for receiving a portion of the output from the laser diode via optics positioned between the laser diode and the pin diode. The optics includes a collimator, a linear polarizer and a polarization beam splitter. The circuitry includes a high gain amplifier which receives the analog signal with a compensating network connected between the amplifier output and the laser diode. The circuitry also has a feedback circuit portion including the pin diode connected to one input of the amplifier.

Laser System with Dynamically Stabilized Transient Wavelength and Method of Operating Same

A method and laser system for dynamically adjusting a transient wavelength of light pulses emitted by a laser includes sequential processing of transient photocurrent curves which are generated after interaction between each light pulse and wavelength-selective medium which is configured with a known spectral peak line selected in the range of the transient wavelength. The method further includes continuously processing parameters of sequentially generated curves until the processed parameters are repeatedly uniform.

Semiconductor laser driver and image forming apparatus incorporating same

A semiconductor laser driver to execute automatic power control (APC) for multiple semiconductor lasers based on a common APC output from an image controller. The semiconductor laser driver includes a drive circuit to generate an individual APC signal to execute APC for each semiconductor laser based on the common APC signal.

Optical pumping of a solid-state gain-medium using a diode-laser bar stack with individually addressable bars

A diode-laser bar stack includes a plurality of diode-laser bars having different temperature dependent peak-emission wavelengths. The stack is arranged such that the bars can be separately powered. This allows one or more of the bars to be “on” while others are “off”. A switching arrangement is described for selectively turning bars on or off, responsive to a signal representative of the temperature of the diode-laser bar stack, for providing a desired total emission spectrum.

Automatic power control (apc) loop for adjusting the bias current of a laser diode

A automatic power control loop comprises a photo diode used for sensing a light intensity of a laser diode to generate a feedback current, a switch selector used for selecting one among a plurality of predetermined currents according to a control signal generated by a controller, a transducer used for transferring a current different between the feedback current and the selected predetermined current into a load voltage, a comparator used for comparing the load voltage with a reference voltage to generate a comparison signal, a counter used for counting a count value according to the comparison signal and the control signal, and a laser diode driver used for generating a corresponding bias current in response to the count value to drive the laser diode. Thereby, the bias current will be adjusted within an allowable range, so that the light source of the laser diode can maintain a constant light intensity.

Method, Circuitry and Apparatus for Outputting a Stable Optical Signal in a Dense Wavelength Division Multiplexing Device During Fast Changes of Operating Conditions

The disclosure relates to a fast and stable method of output wavelength control in a DWDM optical device, and a circuit configured to perform the method. The method and circuit can control of timing and overshoot during conditions of rapid operational changes, such as during power-on or restart of the device. The method and circuit includes optimized APC, TEC and electro-absorption (EA) modulator control hardware and algorithms, to effectively control transient processes. In the present disclosure, software and circuitry based on the method(s) are achieved in part by optimizing APC, EA and TEC control algorithms. The present disclosure combines low-cost methodology and hardware. In combination with hardware/circuit optimization, one can achieve fast turn-on of an optical output signal at a stable wavelength. The method and circuit provides a stable power-up process in which a change of wavelength is small enough to meet DWDM specification requirements, to ensure the elimination and avoidance of crosstalk in adjacent channels in dense wave (sub)systems.

Laser module

[Objective] To prevent change in a direction of an optical axis of a split light within a plane parallel to a surface on which the beam splitter is installed. [Means] A laser module including a laser light source that emits a laser light and a beam splitter that splits a portion of the laser light emitted from the laser light source. The beam splitter includes a first reflective surface and a second reflective surface that are parallel to each other. The first reflective surface transmits a first portion of the laser light and reflects a second portion of the laser light to the second reflective surface. The second reflective surface receives the second portion of the laser light from the first reflective surface and reflects received laser light in a direction parallel to the laser light emitted from the laser light source.

Vertical cavity surface emitting laser with active carrier confinement

It is an object of the present invention to improve the confinement of the carriers within a VCSEL. As a general concept of the invention, it is proposed to integrate a phototransistor layer structure into the layer stack of the VCSEL.

Wavelength tunable laser device, optical module, and method of controlling wavelength tunable laser

Provided is a power saving and highly reliable wavelength tunable laser device. A wavelength tunable laser device 10 of the present invention includes: a wavelength tunable laser 11 including: a laser resonator including a light source 111 and wavelength tunable mechanisms 112 and 113; and light loss control units 114 a and 114 b; a temperature detecting element 12 detecting a temperature of the wavelength tunable laser 11; and a controller 13, wherein the controller 13 obtains temperature information a of the wavelength tunable laser 11 from the temperature detecting element 12, calculates wavelength tunable control parameters d and e and light loss control parameters b 1 and b 2 based on the temperature information a, controls the wavelength tunable mechanisms 112 and 113 based on the wavelength tunable control parameters d and e, and controls light loss control units 114 a and 114 b based on the light loss control parameters b 1 and b 2.

Optical pickup apparatus, integrated circuit, and method for controlling laser output of optical pickup apparatus

An optical-pickup apparatus includes: a first laser light source including a first laser diode to emit a laser beam having a first wavelength, and a back-monitor photodetector to receive the laser beam emitted in a backward direction, not being an optical-disc direction, and output a first monitor signal; a second laser-light source including a second laser diode to emit a laser beam having a second wavelength; a light-receiving circuit including a front-monitor photodetector to receive the laser beam emitted in a forward direction, being the optical-disc direction, and output a second monitor signal, and a switch circuit to be inputted with the first and second monitor signals, and output the first or second monitor signal according to a switch signal; and first and second drive circuits to drive the first and second laser diodes according to the first and second monitor signals outputted from the light-receiving circuit, respectively.

Quantum interference device, atomic oscillator, and magnetic sensor

A quantum interference device includes: gaseous alkali metal atoms; and a light source for causing a resonant light pair having different frequencies that keep a frequency difference equivalent to an energy difference between two ground states of the alkali metal atoms, the quantum interference device causing the alkali metal atoms and the resonant light pair to interact each other to cause an electromagnetically induced transparency phenomenon (EIT), wherein there are a plurality of the resonant light pairs, and center frequencies of the respective resonant light pairs are different from one another.

Frequency stabilized laser system

A laser stabilization system includes laser source having first and second ends; first waveguide portion having first and second ends, first end of first waveguide portion coupled to first end of laser source; second waveguide portion having first and second ends, first end of second waveguide portion coupled to second end of laser source; micro-cavity coupled between second end of first waveguide portion and second end of second waveguide portion, micro-cavity having resonant frequency; and electronic locking loop coupled between micro-cavity and laser source, wherein electronic locking loop electronically locks laser source to resonant frequency of micro-cavity; wherein first waveguide portion is optical locking loop coupled between micro-cavity and laser source, wherein optical locking loop optically locks laser source to resonant frequency of micro-cavity; micro-cavity stabilization loop coupled with micro-cavity, wherein micro-cavity stabilization loop stabilizes resonant frequency of micro-cavity to reference frequency; and output for outputting light from system.

Method to switch emission wavelength of tunable laser diode

The method to change the emission wavelength of a tunable LD is disclosed. In an ordinary state, the method monitors conditions not only relating to determine the emission wavelength but conditions independent of the emission wavelength by an ordinary A/D-C implemented within the controller. Responding to an instruction to switch the emission wavelength, the controller only monitors the former conditions affecting the determination of the emission wavelength. The sampling rate of the ordinary A/D-C is equivalently enhanced without installing an additional A/D-C.

DEVICE AND METHOD FOR CONTROLLING LASING WAVELENGTH OF TUNABLE LASER, AND A WAVELENGTH DIVISION MULTIPLEXED-PASSIVE OPTICAL NETWORK HAVING THE SAME

The present invention discloses a device and method for controlling a lasing wavelength of a tunable laser, and a wavelength division multiplexed-passive optical network having the same. 1. A device for controlling a lasing wavelength of a tunable laser comprising:a wavelength division multiplexer/de-multiplexer (WD MUX/DE-MUX);a single mode fiber (SMF) being connected to the WD MUX/DE-MUX;a tunable laser (TL) for outputting a first light to the WD MUX/DE-MUX;an optical coupler, being provided between the WD MUX/DE-MUX and the TL, for receiving and outputting the first light and for being inputted and outputting a reflected optical component of the first light which is backscattered or reflected from the SMF;a photodiode (PD), being connected to the optical coupler, for converting the reflected optical component into an electric signal upon receipt thereof and outputting the converted electric signal;a wavelength identifier (WLI), being connected to the PD, for indentifying the lasing wavelength of the TL upon receipt of the converted electric signal and outputting an indentifying signal; anda wavelength controller (WLC), being connected to the WLI, for controlling the wavelengths of the TL upon receipt of the indentifying signal.2. The device for controlling a lasing wavelength of a tunable laser of claim 1 , wherein the WLI identifies the lasing wavelength of the TL by using a maximum power characteristic upon receipt of the converted electric signal claim 1 , and outputs an identifying signal.3. The device for controlling a lasing wavelength of a tunable laser of claim 1 , wherein the optical coupler is embodied by an optical circulator.4. The device for controlling a lasing wavelength of a tunable laser of claim 1 , further comprises an optical splitter/reflector claim 1 , being provided between the SMF and the MUX/DE-MUX claim 1 , for receiving and splitting a portion of the first light and outputting a reflected component of the first light.5. The device for ...

PHOTONIC INTEGRATED TRANSMITTER

A photonic integrated circuit transmitter and a method for transmitting optical signals including a mode-locked laser diode generating a frequency comb optical signal and inputting said comb optical signal into a multiplexer/demultiplexer which demultiplexes said comb optical signal into a plurality of individual optical signals. A plurality of reflective modulators each receiving a respective one of said demultiplexed individual optical signals and modulating said received individual optical signal and reflecting the modulated optical signal back to the multiplexer/demultiplexer. The multiplexer/demultiplexer then multiplexes the received modulated optical signal into a multiplexed output optical signal. 1- A photonic integrated circuit transmitter comprising a laser source configured for generating a frequency comb optical signal , a multiplexer/demultiplexer configured for receiving a frequency comb optical signal from the laser source and demultiplex said comb optical signal into a plurality of individual optical signals , a plurality of reflective modulators wherein at least some of said plurality of reflective modulators are each configured for receiving a respective one of said demultiplexed individual optical signals , modulating said received individual optical signal and reflecting the modulated optical signal back to the multiplexer/demultiplexer wherein said multiplexer/demultiplexer is further configured for multiplexing the received modulated optical signal into a multiplexed output optical signal.2- The transmitter of claim 1 , wherein the laser source is a mode-locked laser diode.3- The transmitter of any one of the previous claims comprising a plurality of variable optical attenuators.4- The transmitter of any one of the previous claims further comprising a plurality of semiconductor optical amplifiers.5- The transmitter of any one of the previous claims wherein the multiplexer/demultiplexer is an arrayed waveguide grating.6- The transmitter of any ...

WAVELENGTH DIVISION MULTIPLEXING TRANSMISSION DEVICE

A transmitter to be added or reduced turns ON/OFF an optical output. A relay station and a receiving terminal station acquire the amount of fluctuation of the optical output of the received signal light when the optical output of the added transmitter is turned ON and OFF. From the amount of fluctuation of the optical output, the number of wavelengths after the addition or reduction is acquired. Without an OSC signal, each station may be informed of the number of wavelengths. Therefore, the configuration for transmitting and receiving the OSC signal is not requested, thereby reducing the total cost, appropriately controlling the gain of the optical amplifier, and successfully maintaining transmission quality. 1. A wavelength division multiplexing transmission device in a wavelength division multiplexing transmission system which transmits signal light from a transmitting terminal station , comprising:an optical intensity detection unit configured to detect light intensity of signal light transmitted from the transmitting terminal station when the output of a transmitter added or reduced in the transmitting terminal station is turned ON and OFF; anda wavelength number detection unit configured to detect a number of added or reduced wavelengths from an amount of fluctuation of the light intensity detected by the light intensity detection unit when the output of the transmitter is turned ON and OFF.2. The device according to claim 1 , further comprisingan optical amplification unit configured to amplify the signal light, whereina gain of the optical amplifier is controlled depending on the detected number of wavelengths.3. The device according to claim 2 , whereinbefore the transmitter turns ON and OFF the output, a signal obtained by intensity-modulating the signal light using a signal of a specific pattern is output.4. The device according to claim 3 , whereinwhen the signal intensity-modulated by the specific pattern is received, the optical amplifier is set under ...

CONTROL METHOD AND MEASURING METHOD OF SEMICONDUCTOR OPTICAL AMPLIFIER, AND SEMICONDUCTOR OPTICAL AMPLIFIER DEVICE

A control method of a semiconductor optical amplifier includes: controlling a driving current of the semiconductor optical amplifier in a region where a light output intensity decreases in accordance with increasing of the driving current, a drive current in the region being higher than a drive current in a region where a light output intensity increases in accordance with increasing of the driving current. 1. A control method of a semiconductor optical amplifier comprising:controlling a driving current of the semiconductor optical amplifier in a region where a light output intensity decreases in accordance with increasing of the driving current, a drive current in the region being higher than a drive current in a region where a light output intensity increases in accordance with increasing of the driving current.2. The control method according to claim 1 , whereinthe semiconductor optical amplifier has output characteristics including a first region in which a light output intensity increases with increase in driving current, a second region in which a driving current is higher than that in the first region and the light output intensity reaches saturation with increase in driving current, and a third region in which the driving current is higher than that in the second region and the light output intensity decreases with increase in driving current, andthe driving current of the semiconductor optical amplifier is in the third region.3. The control method according to claim 1 , whereina light output intensity of the semiconductor optical amplifier is 0.4 dB or more smaller than a peak of the light output intensity of the semiconductor optical amplifier.4. The control method according to claim 1 , whereina light source of the semiconductor optical amplifier is intensity-modulated light beam.5. The control method according to claim 1 , whereinthe driving current is feedback-controlled to a target value of a light output intensity of the semiconductor optical ...

Small packaged tunable laser assembly

A tunable laser configured in a small package coupled to a printed circuit board. The tunable laser includes a housing with a volume formed by exterior walls. An electrical input interface is positioned at the first end of the housing. An optical output interface is positioned at the second end of the housing and configured to transmit a continuous wave optical beam. A beam splitter and photodiode is disposed in the path of the laser beam for determining the emitted intensity of the laser beam, and an optical isolator is positioned downstream of the beam splitter to prevent the incoming light from the beam splitter from reflecting back though the beam splitter and into the cavity of the laser.

EXTERNAL CAVITY LASER ARRAY SYSTEM AND WDM OPTICAL SYSTEM INCLUDING SAME

An external cavity laser array system may be used in a WDM optical system, such as a WDM-PON, for transmitting optical signals at multiple channel wavelengths. The system generally includes a plurality of laser emitters (e.g., gain chips) optically coupled to and separated from respective exit reflectors (e.g., tunable narrow-band reflectors), thereby forming an array of external cavity lasers with extended lasing cavities. The exit reflectors may be distributed Bragg reflectors (DBRs) located in the waveguides in an arrayed waveguide grating (AWG). The laser emitters emit a range of wavelengths including multiple channel wavelengths and the DBRs reflect a subset of channel wavelengths including at least a channel wavelength associated with the laser emitter such that lasing occurs at the subset of channel wavelengths. The AWG then filters the emitted laser light at the associated channel wavelengths. 1. An external cavity laser array system comprising:a plurality of laser emitters, each of the laser emitters including a gain region for emitting light across a range of wavelengths and a back reflector located at one end thereof; andan arrayed waveguide grating (AWG) including a plurality of input ports optically coupled to the laser emitters, respectively, an output port, and a plurality of optical waveguides extending from the input ports, respectively, to the output port, wherein the optical waveguides include distributed Bragg reflector (DBR) gratings, respectively, such that extended lasing cavities are formed between the back reflectors of the laser emitters and the DBR gratings, respectively.2. The external cavity laser array system of wherein the laser emitters include reflective-semiconductor-optical-amplifiers (R-SOAs).3. The external cavity laser array system of further comprising an optical assembly for optically coupling the emitted light into the respective waveguides of the AWG.4. The external cavity laser array system of wherein each of the DBR ...

OPTICAL RECEIVER IMPLEMENTED WITH SEMICONDUCTOR OPTICAL AMPLIFIER IN FRONT END THEREOF AND METHOD TO CONTROL THE SAME

An optical receiver implemented with a semiconductor amplifier (SOA) whose temperature is controlled by the automatic temperature control (ATC) circuit is disclosed. The optical receiver further includes an optical de-multiplexer, optical devices, a signal processor, and a controller. The controller monitors a temperature of the SOA and time derivatives thereof. The controller activates the optical devices and the signal processor after the time derivative of the temperature of the SOA becomes less than a reference. 1. An optical receiver , comprising:a semiconductor optical amplifier (SOA) configured to receive an optical signal and output an amplified optical signal, the optical signal containing a plurality of signals each having a wavelength specific thereto and different from others;an optical de-multiplexer configured to de-multiplex the amplified optical signal into a plurality of de-multiplexed optical signals depending on the wavelength thereof;a plurality of optical devices configured to convert de-multiplexed optical signals into electrical signals;a signal processor configured to recover data contained in the electrical signals and to extract a clock contained in at least one of electrical signals; anda controller configured to activate the optical devices and the signal processor after the SOA stabilizes a temperature thereon in a target temperature.2. The optical receiver of claim 1 ,wherein the controller includes a first register, an arithmetical unit, and a comparator, the first register holding a current temperature of the SOA and a previous temperature of the SOA sensed previously by a preset period, the arithmetical unit calculating a time derivative of the temperature of the SOA by subtracting the previous temperature from the current temperature, the comparator comparing the time derivative with a first preset reference, andwherein the controller decides the temperature of the SOA becomes stable when the time derivative of the temperature of ...

OPTICAL TRANSMISSION APPARATUS

An optical transmission apparatus according to the present invention includes: wave splitter () splitting an input optical signal into a plurality of wavelength bands; a plurality of optical switches (-) composed of optical shutters or variable optical attenuators that pass or shut off split optical signals corresponding to a plurality of optical signals split by wave splitter (); optical coupler () combining optical signals that are output from the plurality of optical switches (-); and control section () setting up each of the plurality of optical switches (-), in which each of the plurality of optical switches is in a state of passing the split optical signals or in a state of shutting-off the split optical signals. 1. An optical transmission apparatus , comprising:a wave splitter splitting an input optical signal into a plurality of wavelength bands;a plurality of optical switches composed of optical shutters or variable optical attenuators that pass or shut off split optical signals corresponding to a plurality of optical signals split by said wave splitter;a first optical coupler combining optical signals that are output from said plurality of optical switches; anda control section setting up each of said plurality of optical switches, in which each of said plurality of optical switches is in a state of passing said split optical signals or in a state of shutting-off said split optical signals.2. The optical transmission apparatus according to claim 1 ,wherein said wave splitter is a reflection type optical filter that passes an optical signal having a predetermined wavelength band of said input optical signal and reflects an optical signal having a wavelength band other than the predetermined wavelength band.3. The optical transmission apparatus according to claim 2 ,wherein said wave splitter has a structure in which said reflection type optical filters are connected in multiple stages.4. The optical transmission apparatus according to claim 1 ,wherein said ...

PULSE LIGHT SOURCE

The pulse light source comprises a semiconductor laser outputting pulse light, an optical filter, and an optical amplifier. The optical filter outputs a chirping component of the inputted pulse light, by adjusting a relative position of a transmission spectrum of the optical filter with respect to an output spectrum of the seed light source. 1. A pulse light source , comprising:a semiconductor laser which is directly modulated and outputs pulse light;a first optical filter which inputs the pulse light from the semiconductor laser and selectively outputs a chirping component of the inputted pulse light, the first optical filter being provided on an optical path between the semiconductor laser and an output end of the pulse light source:a first optical amplifier which inputs the pulse light from the semiconductor laser and amplifies the inputted pulse light, the first optical amplifier being provided on the optical path between the semiconductor laser and the output end.2. The pulse light source according to claim 1 , wherein the semiconductor laser outputs the pulse light that overshoots at a rising thereof.3. The pulse light source according to claim 1 , wherein a center wavelength of a transmission spectrum of the first optical filter is adjustable.4. The pulse light source according to claim 3 , wherein the center wavelength of the transmission spectrum of the first optical filter is set in a long wavelength side from a peak wavelength of the pulse light.5. The pulse light source according to claim 3 , wherein the transmission spectrum of the first optical filter has a full width at half maximum of 3 nm.6. The pulse light source according to claim 1 , wherein the optical filter is provided on an optical path between the semiconductor laser and the first optical amplifier.7. The pulse light source according to claim 6 , further comprising a second optical amplifier provided on an optical path between the semiconductor laser and the first optical filter.8. The pulse ...

Temperature Measurement And Control For Laser And Light-Emitting Diodes

The existing diodes in an LED or laser diode package are used to measure the junction temperature of the LED or laser diode. The light or laser emissions of a diode are switched off by removing the operational drive current applied to the diode package. A reference current, which can be lower the operational drive current, is applied to the diode package. The resulting forward voltage of the diode is measured using a voltage measurement circuit. Using the inherent current-voltage-temperature relationship of the diode, the actual junction temperature of the diode can be determined. The resulting forward voltage can be used in a feedback loop to provide temperature regulation of the diode package, with or without determining the actual junction temperature. The measured forward voltage of a photodiode or the emissions diode in a diode package can be used to determine the junction temperature of the emissions diode. 1. A circuit , comprising:an emission diode;a photodiode;a voltage measurement circuit configured to measure at least one of a forward voltage of the emission diode or a forward voltage of the photodiode; anda control circuit configured to control an operating temperature of the emission diode based on the at least one measured forward voltage and a target operating temperature that is equal to a characterized operating temperature of the emission diode when producing emissions at a predetermined wavelength.2. The circuit of claim 1 , wherein:the at least one measured forward voltage includes the measured forward voltage of the emission diode;the emission diode comprises a diode junction; andthe measured forward voltage of the emission diode is across the diode junction of the emission diode.3. The circuit of claim 2 , wherein:the control circuit controls the operating temperature of the emission diode based on the measured forward voltage of the emission diode and the target operating temperature by comparing the measured forward voltage of the emission ...

Method and Apparatus for Controlling Optical Power

A method can be used for controlling optical power. Output optical power of an optical source is monitored and it is determined whether a preset test control signal is received. When the preset test control signal is not received, a data signal is modulated to output light of the optical source and a bias current of the optical source is adjusted according to an output optical power monitoring result of the optical source to implement automatic power control. When the preset test control signal is received, a test is started and a test signal is superimposed to the data signal to form a superimposed signal. The superimposed signal is modulated to the output light of the optical source. The output optical power monitoring result of the optical source is ignored during the test period to maintain the bias current of the optical source at a preset target value.

MODULATED LIGHT SOURCE

A modulated light source includes a ring modulator, a first optical waveguide and a second optical waveguide that are optically connected to the ring modulator, and a third optical waveguide that optically connects an end of the first optical waveguide and an end of the second optical waveguide. At least part of the third optical waveguide has optical gain, and an optical waveguide loop including the ring modulator, the first optical waveguide, the second optical waveguide, and the third optical waveguide is used as a resonator to cause laser oscillation. 1. A modulated light source comprising:a ring modulator;a first optical waveguide and a second optical waveguide that are optically connected to the ring modulator; anda third optical waveguide that optically connects an end of the first optical waveguide and an end of the second optical waveguide,wherein at least part of the third optical waveguide has optical gain, andan optical waveguide loop including the ring modulator, the first optical waveguide, the second optical waveguide, and the third optical waveguide is used as a resonator to cause laser oscillation.2. The modulated light source according to claim 1 , wherein a transmission wavelength band between the end of the first optical waveguide and the end of the second optical waveguide has a size that allows selecting one of a plurality of longitudinal modes in which laser oscillation is possible to occur claim 1 , and the laser oscillation occurs in a single longitudinal mode.3. The modulated light source according to claim 1 ,wherein the first optical waveguide has another end having a mirror, andthe second optical waveguide has another end serving as a light output port.4. The modulated light source according to claim 1 , including a plurality of optical waveguide loops each identical to the optical waveguide loop claim 1 ,wherein in two adjacent optical waveguide loops out of the optical waveguide loops, another end of the second optical waveguide of one ...

COMPACT TUNABLE LASER DEVICE

The present invention relates to a compact tunable laser device that can change the oscillation laser wavelength. The laser device includes: a laser diode chip that emits laser light; an optical feedback-partial reflective mirror that feeds some of light emitted from the laser diode chip back to the laser diode chip by reflecting it; a collimating lens that is disposed in a light path between the laser diode chip and the optical feedback-partial reflective mirror and collimates light emitted from the laser diode chip a tunable-selective filter of which the transmissive wavelength changes in accordance with temperature; and a 45°-reflective mirror that changes laser light traveling horizontally to a package bottom into laser light traveling perpendicular to the package bottom, wherein the laser diode chip or the tunable-selective filter is disposed on a thermoelectric element and has an oscillation wavelength changing in accordance with a change in temperature of the thermoelectric element 1. A semiconductor laser device comprising:{'b': '100', 'a laser diode chip () that emits laser light;'}{'b': 500', '100', '100, 'an optical feedback-partial reflective mirror () that feeds some of light emitted from the laser diode chip () back to the laser diode chip () by reflecting it;'}{'b': 200', '100', '500', '100, 'a collimating lens () that is disposed in a light path between the laser diode chip () and the optical feedback-partial reflective mirror () and collimates light emitted from the laser diode chip ();'}{'b': '300', 'a tunable-selective filter () of which the transmissive wavelength changes in accordance with temperature; and'}{'b': '400', 'a 45°-reflective mirror () that changes laser light traveling horizontally to a package bottom into laser light traveling perpendicular to the package bottom,'}{'b': 100', '300', '900', '900, 'wherein the laser diode chip () or the tunable-selective filter () is disposed on a thermoelectric element () and has an oscillation ...

LASER APPARATUS AND METHOD TO RE-TUNE EMISSION WAVELENGTH OF WAVELENGTH TUNABLE LD

A laser apparatus for tuning the emission wavelength of a wavelength tunable laser diode will be described. The apparatus includes a tunable LD with heaters to tune the emission wavelength of the tunable LD, and a controller to control the power supplied to the heaters. A feature of the laser apparatus is that the controller supplies pre-emphasis power to the heaters before the supplement of the power corresponding to the re-tuned emission wavelength to accelerate the stability of the temperature of the heaters. 1. A laser apparatus , comprisinga wavelength tunable laser diode (t-LD) providing a heater; anda controller to control power supplied to the heater to re-tune an emission wavelength of the t-LD by changing the power from first power Pa to second power Pb,wherein the controller supplies pre-emphasis power Pp before supplying the second power Pb, the pre-emphasis power Pp being greater than the second power Pb when the second power Pb is greater than the first power Pa, and supplies the pre-emphasis power Pp smaller than the second power Pb when the second power Pb is smaller than the first power Pa.2. The laser apparatus of claim 1 , {'br': None, 'i': Pp=Pb+K', 'Pb−Pa, '·(),'}, 'wherein the power Pp is determined by an equation ofwhere K is a coefficient.3. The laser apparatus of claim 2 ,wherein the t-LD provides n (>1) counts of heaters each supplied with first power Pai, second power Pbi, and pre-emphasis power Ppi specific to respective heaters, {'br': None, 'i': Ppi=Pbi+Ki', 'Pbi−Pai', 'i=', 'n,, '×()1 to'}, 'wherein respective pre-emphasis power Ppi are determined by equations ofwherein Ki is specific to the i-th heater.4. The laser apparatus of claim 2 ,wherein the coefficient K depends on a difference between the first power Pa and the second power Pb.5. The laser apparatus of claim 2 ,wherein the coefficient K depends on a polarity of a difference between the first power Pa and the second power Pb.6. The laser apparatus of claim 2 ,wherein the ...

LASER DRIVER INCORPORATING CLAMPING CIRCUIT WITH FREEWHEELING DIODE

A level-shifter includes an input node coupled to a laser driver input receiving a trigger signal, the input node receiving a signal indicating generation of a laser drive-pulse. A p-channel transistor has a source coupled to a supply node, a drain coupled to an output node, and a gate coupled to the input node. An n-channel transistor has a drain coupled to the drain of the p-channel transistor, a source coupled to ground, and a gate coupled to the input node. A first switch couples the input node to the output node. Another p-channel transistor has a source coupled to the supply node, a drain coupled to the output node by a second switch, and a gate coupled to the input node. The first switch closes and second switch opens when the signal is low, and the first switch opens and second switch closes when the signal is high. 1. A system comprising: an input node capacitively coupled to a laser driver and configured to receive a signal therefrom indicative of generation of a laser drive pulse; and', 'an inverter having an input coupled to the input node and an output coupled to an output node, the inverter having adjustable threshold voltage that increases when the signal on the input node goes high and decreases when the signal on the input node returns low., 'a level shifter, comprising2. The system of claim 1 , wherein the level shifter further comprises:a buffer having an input coupled to the output node; anda current source generating a current proportional to absolute temperature, the current source biasing the buffer with the current proportional to absolute temperature.3. The system of claim 1 , wherein the inverter comprises:a first p-channel transistor having a source coupled to a supply node, a drain coupled to the output node, and a gate coupled to the input node;an n-channel transistor having a drain coupled to the output node, a source coupled to ground, and a gate coupled to the input node;a first switch selectively coupling the input node to the output ...

INTEGRATED INTER-CAVITY PHOTODETECTOR FOR LASER POWER AND THRESHOLD ESTIMATION

A multi-section laser device is configured with a gain section and an integrated photodetector section. The photodetector section, rather than being a separate component, is integrated directly into the body of the laser. The integrated photodetector section absorbs photons generated by the gain section and creates a photocurrent that is proportional to the output of the multi-section laser device. The measured photocurrent is usable to calculate power output of the multi-section laser device and to identify any adjustments that may be needed to be made to the laser in order to achieve desired laser light output. 1. A multi-section laser device comprising:a gain section that is electrically biased in a forward direction; anda photodetector section that is electrically biased in a reverse direction, the photodetector section being controllable independently of the gain section;wherein the photodetector section is configured to absorb a portion of the photons generated by the gain section and to generate photocurrent that is proportional to an output power of the multi-section laser device such that the photodetector section is usable to determine the output power of the multi-section laser device.2. The multi-section laser device according to claim 1 , wherein the photodetector section is positioned between the gain section and a light emitting facet of the multi-section laser device.3. The multi-section laser device according to further comprising an unpumped section claim 2 , wherein the photodetector section is positioned directly adjacent to the unpumped section of the multi-section laser claim 2 , such that the photodetector section and the unpumped section share a common bounding edge.4. The multi-section laser device according to claim 1 , wherein the gain section is positioned between the photodetector section and a light emitting facet of the multi-section laser device.5. The multi-section laser device according to claim 1 , wherein the photodetector section ...

OPTICAL MODULE

An optical module includes a semiconductor laser element, a lens configured to collect emitted light that is emitted from the semiconductor laser element, a cap configured to hold the lens and hermetically seal the semiconductor laser element, a monitor light-receiving element configured to receive backlight of the semiconductor laser element, a transmission plate arranged between the semiconductor laser element and the monitor light-receiving element and configured to attenuate the backlight according to decrease in a temperature around the cap so as to cause the backlight to enter the monitor light-receiving element, and a control unit configured to control an injection current of the semiconductor laser element such that an output of the monitor light-receiving element is kept at a constant level. 1. An optical module comprising:a semiconductor laser element;a thermoelectric cooler configured to controls the temperature of the semiconductor laser element at a constant level;a lens configured to collect emitted light that is emitted from the semiconductor laser element;a stem, the thermoelectric cooler is fixed to the stem;a metal post fixed to the stem;a cap configured to hold the lens and hermetically seal the semiconductor laser element, the cap is fixed to the stem;a monitor light-receiving element configured to receive backlight of the semiconductor laser element;a transmission plate arranged between the semiconductor laser element and the monitor light-receiving element and configured to attenuate the backlight according to decrease in a temperature of the transmission plate so as to cause the backlight to enter the monitor light-receiving element, the transmission plate is away from both the semiconductor laser element and the monitor light-receiving element, the transmission plate is fixed to the metal post;a controller configured to control an injection current of the semiconductor laser element such that an output of the monitor light-receiving element ...

SEMICONDUCTOR LASER

Provided is a semiconductor laser including: a core layer having an active layer and a diffraction grating layer optically coupled to the active layer; and paired clad layers arranged sandwiching the core layer, and formed with a waveguide along the core layer, and the semiconductor laser includes: a flat layer provided continuously with the diffraction grating layer along the waveguide; and a temperature control mechanism for controlling the temperature of the flat layer to a temperature different from that of the diffraction grating layer. 1. A semiconductor laser comprising: a core layer having an active layer and a diffraction grating layer optically coupled to the active layer; and paired clad layers arranged sandwiching the core layer , and formed with a waveguide along the core layer , the semiconductor laser comprising:a flat layer provided continuously with the diffraction grating layer along the waveguide; anda temperature control mechanism for controlling temperature of the flat layer to a temperature different from the diffraction grating layer.2. The semiconductor laser according to claim 1 , whereinone end and the other end of the waveguide are respectively provided with a reflective surface and a light lead-out surface, andan end surface of the flat layer serves as the reflective surface.3. The semiconductor laser according to claim 2 , whereinthe temperature is controlled by the temperature control mechanism so that a phase of light reflected at the end surface of the flat layer is shifted to λ/4.4. The semiconductor laser according to claim 1 , configured so thatthe temperature control mechanism is one including a temperature control electrode provided in a site corresponding to the flat layer, and the temperature of the flat layer can be controlled by applying current to the flat layer via the temperature control electrode.5. The semiconductor laser according to claim 1 , whereinthe active layer is formed of a multiple quantum well structure in ...

WAVELENGTH LOCKER USING MULTIPLE FEEDBACK CURVES TO WAVELENGTH LOCK A BEAM

A device may include a first photodetector to generate a first current based on an optical power of an optical beam. The device may include a beam splitter to split a portion of the optical beam into a first beam and a second beam. The device may include a wavelength filter to filter the first beam and the second beam. The wavelength filter may filter the second beam differently than the first beam based on a difference between an optical path length of the first beam and an optical path length of the second beam through the wavelength filter. The device may include second and third photodetectors to respectively receive, after the wavelength filter, the first beam and the second beam and to generate respective second currents. 126-. (canceled)27. A device , comprising:a laser emitter to generate a laser beam to be wavelength locked to a target frequency based on an emission frequency to be measured by the device; 'the laser beam to be wavelength locked based on the first current;', 'a first photodetector to generate a first current based on a first optical power of the laser beam,'}a beam splitter to split a portion of the laser beam into a first beam and a second beam; the patterned etalon to have different optical path lengths for the first beam and the second beam, and', 'the patterned etalon to filter the first beam and the second beam to a second optical power and a third optical power, respectively, based on the different optical path lengths; and, 'a patterned etalon to filter the first beam and the second beam,'} 'a selected current, of the respective second currents, to be used to wavelength lock the laser beam.', 'second and third photodetectors to generate respective second currents,'}28. The device of claim 27 , wherethe beam splitter is further to split the portion of the laser beam into a third beam and a fourth beam, andthe third beam is received by the first photodetector without being filtered by the patterned etalon.29. The device of claim 27 , ...

METHOD OF EVALUATING INITIAL PARAMETERS AND TARGET VALUES FOR FEEDBACK CONTROL LOOP OF WAVELENGTH TUNABLE SYSTEM

A method of determining initial parameters and target values for tuning an emission wavelength of a wavelength tunable laser capable of emitting laser light in a substantial wavelength range is disclosed. The method iterates an evaluation of initial parameters and target values at target wavelengths in a preset order. The evaluation includes steps of supplying empirically obtained parameters to the t-LD, confirming whether the t-LD generates an optical beams, determining the initial parameters and the target values by carrying out feedback loops of the AFC and the APC when the t-LD generates the optical beam, or shifting the wavelength range so as to exclude the current target wavelength when the t-LD generates no optical beam. 1. A method of ranking a wavelength tunable laser (t-LD) that provides a sampled grating distributed feedback (SG-DFB) region , a chirped sampled grating distributed feedback reflector (CSG-DBR) region , and a semiconductor optical amplifier (SOA) region , the t-LD being mounted on a thermo-electric cooler (TEC) that varies a temperature of the t-LD , the CSG-DBR region providing a heater that varies a temperature of the CSG-DBR region , the t-LD emitting laser light whose wavelength being to be discretely tunable within a wavelength range by setting parameters in the t-LD , the SG-DFB region having an optical gain that shows a maximum in a center of the wavelength range and becomes relatively smaller in peripheries of the wavelength range , the method comprising steps of:driving the t-LD nearby a shortest wavelength and nearby a longest wavelength within the wavelength range by setting parameters that are empirically determined;confirming whether the t-LD generates an optical beam whose wavelength is around the shortest wavelength and the longest wavelength in the wavelength range with and power is around a designed power, degrading a rank of the t-LD, and', 'iterating a step of driving the t-LD at a wavelength next to the shortest ...

LIGHT EMITTING MODULES WITH IRREGULAR AND/OR APERIODIC CONDUCTIVE TRACES

An example system includes an optical element defining a first surface, and a substrate layer defining a second surface and a third surface opposite the second surface. The second surface of the substrate layer is adjacent the first surface the optical element. The system also includes a conductive trace disposed on the third surface of the substrate layer. The optical element is operable to emit light in a first direction through the substrate layer and the conductive trace. The conductive trace defines at least one of an aperiodic path or an irregular path. 1. A system comprising:an optical element defining a first surface;a substrate layer defining a second surface, and a third surface opposite the second surface, wherein the second surface of the substrate layer is adjacent the first surface the optical element; anda conductive trace disposed on the third surface of the substrate layer;wherein the optical element is operable to emit light in a first direction through the substrate layer and the conductive trace, andwherein the conductive trace defines at least one of an aperiodic path or an irregular path.2. The system of claim 1 , wherein the conductive trace comprises two or more first conductive segments claim 1 , wherein each of the first conductive segments is parallel to each of the other first conductive segments claim 1 , and wherein the first conductive segments have a common length claim 1 , andwherein at least one of the first conductive segments has a width that is different from a width of at least one of the other first conductive segments.3. The system of claim 2 , wherein the third surface of the substrate layer comprises a central region and a peripheral region surrounding the central region claim 2 , and wherein the first conductive segments are disposed claim 2 , at least in part claim 2 , on the central region of the third surface of the substrate layer.4. The system of claim 1 , wherein the conductive trace comprises two or more first ...

SEMICONDUCTOR LASER MODULE

A surface emitting laser element capable of emitting a main beam and a sub-beam, and a monitoring light detection element capable of detecting a light intensity of the sub-beam are included, the surface emitting laser element is a PCSEL, the main beam and the sub-beam are emitted in an upward direction of the surface emitting laser element and are inclined to each other at a predetermined angle, and respective changes in a peak light intensity of the main beam and a peak light intensity of the sub-beam with respect to a value of a driving current of the surface emitting laser element are correlated with each other. Therefore, if an output of the monitoring light detection element indicating the peak light intensity of the sub-beam is used, the peak light intensity of the main beam can be estimated. 1. A semiconductor laser module , comprising:a surface emitting laser element;a monitoring light detection element; anda storage container,wherein the storage container includes an upper wall and a bottom wall,the storage container stores the surface emitting laser element and the monitoring light detection element,the upper wall includes an opening and faces the bottom wall,the surface emitting laser element includes a principal surface, a light emitting region, and a two-dimensional photonic crystal layer, is provided on the bottom wall, emits a main beam and a sub-beam from the light emitting region, and is arranged so that the main beam passes through the opening,the light emitting region is provided on the principal surface,a first optical axis of the main beam extends in a vertical direction of the principal surface,a second optical axis of the sub-beam forms a predetermined angle a with the vertical direction,the two-dimensional photonic crystal layer includes a plurality of hole portions and extends along the principal surface,the plurality of hole portions have a same shape, are arranged in a lattice pattern in a plurality of arrangement directions parallel to ...

LASER DIODE DRIVER DAMPING CIRCUIT

A damping circuit having an input terminal and an output terminal is described. The damping circuit comprises a driver having an input and an output; an RC circuit coupled between the input terminal and the output; and a resistor coupled between the output and the output terminal, wherein the RC circuit delays passing a signal from the output terminal to the input terminal and a low impedance associated with the driver generally reduces ringing. 1. A damping circuit , comprising:an output terminal;a first transistor having a first control node connected to form a first diode, and a first current node coupled with the output terminal;a second transistor having a second control node connected to form a second diode, and a second current node coupled to the first control node of the first transistor;a buffer circuit coupled with the output terminal and the first transistor; anda resistive-capacitive (RC) circuit coupled between the buffer circuit and the second control node of the second transistor.2. The damping circuit of claim 1 , wherein the buffer circuit includes:a third transistor configured to generate a feedback voltage controlled by the second control node of the second transistor and having a delay established by the RC circuit; anda fourth transistor coupled to the third transistor, the fourth transistor configured to damp the output terminal based on the feedback voltage.3. The damping circuit of claim 1 , wherein the first transistor includes a first NPN transistor having:a first collector node configured to receive a first bias current;a first base node as the first control node, the first base node connected to the first collector node to form the first diode; anda first emitter node as the first current node coupled with the output terminal.4. The damping circuit of claim 3 , wherein the second transistor includes a first PNP transistor having:a second emitter node as the second current node coupled to the first base node of the first NPN transistor;a ...

Systems and Methods for Calibrating, Operating, and Setting a Laser Diode in a Weapon

Systems and methods for calibrating, operating, and setting the magnitude of the power of light provided by a laser diode in a conducted electrical weapon (“CEW”). The light of the laser diode assists in targeting by providing a visible indication of the projected point of impact of the tethered electrode of the CEW. The calibration process enables laser diode of a CEW to operate within regional guidelines of the maximum output power of light permitted by a laser. The method further permits the magnitude of the power of the light provided by a laser diode to be set and operated in changing environmental conditions in the field. 1. A weapon that cooperates with a provided tester , the weapon comprising:a processing circuit;a laser diode; and provide a first signal at a first duty cycle to set an operating point of the laser diode;', 'provide a second signal at a second duty cycle, the second signal turns the laser diode on and off in accordance with the second duty cycle to establish a power of a light provided by the laser diode during a period of the second signal;', 'receive a message from the tester regarding a magnitude of the power as measured by the tester;', 'compare the magnitude of the power to a predetermined range;', 'adjust at least one of the first duty cycle and the second duty cycle responsive to the comparison;', 'repeat receive, compare, and adjust until the magnitude of the power is within the predetermined range., 'a memory having computer-executable instructions stored thereon that, in response to execution by the processing circuit, cause the weapon to2. The weapon of wherein the second duty cycle is about 50 percent.3. The weapon of wherein an active edge of the second signal is synchronous with an active edge of the first signal.4. The weapon of wherein the second signal is generated from the first signal using a divide-by-two counter.5. The weapon of further comprising a photo diode and a resistor coupled to the photo diode claim 1 , wherein: ...

HISTOGRAM BASED OPTIMIZATION FOR OPTICAL MODULATION

The present invention is directed to communication systems and methods. In a specific embodiment, the present invention provides an optical receiver that receives a data stream from an optical transmitter. The optical receiver determines a histogram contour parameter using the data stream and inserts the histogram contour parameter into a back-channel data segment, which is then transmitted to the optical transmitter. The optical transmitter changes its data transmission setting based on the histogram contour parameter. There are other embodiments as well. 1. An optical transceiver apparatus comprising:an optical receiver for converting incoming optical signals to incoming electrical signals;a digital signal processor (DSP) configured to analyze the incoming electrical signals and to generate a histogram characterizing the incoming electrical signals;a forward error correction (FEC) module for encoding the incoming electrical signal;a control module configured process the incoming electrical signal and to generate a signal quality value based on the histogram, the signal quality value being calculated using a quadratic fit of the histogram, the control module being further configured to generate back-channel data based at least on the signal quality value, the control module further being configured to insert the back-channel data to an outgoing data stream; andan optical transmitter for generating output optical signals based on the outgoing data stream.2. The apparatus of wherein the FEC module is configured encapsulate the back-channel data and a portion of the outgoing data stream into an FEC frame.3. The apparatus of wherein the optical transmitter comprises a laser device.4. The apparatus of wherein the control module is configured to change one or more settings for the laser device based on received back-channel data embedded in the incoming electrical signals.5. The apparatus of wherein the one or more settings include a laser wavelength.6. The apparatus of ...

LASER STABILIZING SYSTEM AND LASER SOURCE MODULE

A laser stabilizing system configured to stabilize a laser beam emitted from a laser source includes a beam steering device, a first beam splitter, a first light detector, a second beam splitter, and a second light detector. The beam steering device is configured to steer a direction and a position of the laser beam in four or more degrees of freedom. The first beam splitter is configured to split the laser beam from the beam steering device into a first partial beam and a second partial beam. The first light detector is disposed on a transmission path of the first partial beam. The second beam splitter is configured to split the second partial beam into a third partial beam and a fourth partial beam. The second light detector is disposed on a transmission path of the third partial beam. A laser source module is also provided. 1. A laser stabilizing system configured to stabilize a laser beam emitted from a laser source , the laser stabilizing system comprising:a beam steering device disposed on a path of the laser beam and configured to steer a direction and a position of the laser beam in four or more degrees of freedom;a first beam splitter disposed on a path of the laser beam from the beam steering device and configured to split the laser beam into a first partial beam and a second partial beam;a first light detector disposed on a transmission path of the first partial beam;a second beam splitter disposed on a transmission path of the second partial beam and configured to split the second partial beam into a third partial beam and a fourth partial beam; anda second light detector disposed on a transmission path of the third partial beam.2. The laser stabilizing system according to claim 1 , wherein the beam steering device comprises:a first prism having a first inclined reflecting surface; anda second prism having a second inclined reflecting surface, wherein the laser beam is sequentially reflected by the first inclined reflecting surface and the second ...

OPTICAL LINE TESTING DEVICE USING WAVELENGTH TUNABLE LASER

An optical line testing device for measuring at least a cutting position of an optical line according to the present invention includes: a first wavelength tunable laser source configured to generate a first optical signal in which a plurality of wavelengths appear alternately and periodically; a second wavelength tunable laser source configured to generate a second optical signal which is identical to the first optical signal but has an adjustable delay time; and an interferometer configured to cause interference between a reflected optical signal, corresponding to the first optical signal, which is returning after having been emitted to the optical line, and the second optical signal to output an interference signal. 19-. (canceled)10. An optical line testing device for measuring at least a cutting position of an optical line , the optical line testing device comprising:a first wavelength tunable laser source configured to generate a first optical signal in which a plurality of wavelengths appear alternately and periodically (hereinafter, a period in which one wavelength appears repeatedly is referred to as a ‘wavelength repetition period’);a second wavelength tunable laser source configured to generate a second optical signal which is identical to the first optical signal but has an adjustable delay time; andan interferometer configured to cause interference between a reflected optical signal, corresponding to the first optical signal, which is returning after having been emitted to the optical line, and the second optical signal to output an interference signal, andthe optical line testing is configured to measure the output of the interference signal while varying the delay time.11. The optical line testing device of claim 10 , whereinthe optical line testing device is configured to calculate the cutting position by using a delay time at which the measured output becomes maximum.12. The optical line testing device of claim 10 , whereinthe optical line testing ...

LASER SIDE MODE SUPPRESSION RATIO CONTROL

Laser Side Mode Suppression Ratio (SMSR) control is provided via a logic controller configured to measure an SMSR of a carrier wave upstream of a modulator and measure an Average Optical Power (AOP) of the carrier wave downstream of the modulator; transmit a bias voltage based on the SMSR and the AOP to a laser driver for a laser generating the carrier wave; and transmit an attenuation level based on the SMSR and the AOP to a Variable Optical Attenuator (VOA) upstream of the modulator. In various embodiments the attenuation level and bias voltage can rise or fall together, or one may rise and one may fall to ensure the output optical signal meets specified SMSR and AOP values. 1. A system , comprising:a laser;a photodiode;a Side Mode Suppression Ratio (SMSR) sensor optically connected to the laser;a Variable Optical Attenuator (VOA) optically connected to the laser;an optical modulator having an input side connected to the VOA and an output side connected to the photodiode; anda logic controller electrically connected to the laser, the photodiode, the SMSR sensor, and the VOA, configured to adjust a bias of the laser and an attenuation level of the VOA based on an SMSR target, an SMSR reading from the SMSR sensor, and an optical power reading from the photodiode.2. The system of claim 1 , wherein the logic controller is further configured to adjust the bias and the attenuation level to maintain the optical power according to a predefined output power range.3. The system of claim 1 , further comprising:a first tap disposed between the laser and both the SMSR sensor and the VOA that provides a first portion of a beam generated by the laser to the SMSR sensor and a second portion of the beam to the VOA, wherein the second portion includes more optical power than the first portion; anda second tap disposed between the optical modulator and both the photodiode and an output path that provides a third portion of the beam to the photodiode and a fourth portion of the beam ...

LASER POWER CONTROLLER

A laser power controller employs: selection circuitry configured to select one of a data input value, a logical high value or a logical low value such that the selection circuitry selects the data input value during a data transmission period during a defined burst period and selects one of the logical high value and the logical low value during an extension time period during the defined burst period and immediately following the data transmission period; drive circuitry configured to apply, to a laser diode, a current corresponding to the value selected by the selection circuitry during the defined burst period or a zero value otherwise, the current being such that the laser diode is configured to provide an optical output; an optical sensor module configured to provide a sensor module output corresponding to the optical output of the laser diode, and configured to provide an electrical output proportional to the laser diode's optical output corresponding to the logical high value or the logical low value; and a controller configured to receive desired values regarding minimum and maximum optical output power levels of the laser diode and to receive the electrical output from the optical sensor module proportional to the optical output power level corresponding to the logical high and the logical low values; the controller being configured to use the received information to provide control values for the drive circuitry. 1. A system comprising:selection circuitry configured to select one of a data input value, a logical high value or a logical low value such that the selection circuitry selects the data input value during a data transmission period during a defined burst period and selects one of the logical high value and the logical low value during an extension time period during the defined burst period and immediately following the data transmission period;drive circuitry configured to apply a current to a laser diode, the current corresponding to the value ...

METHODS AND APPARATUS TO CONTROL THE OPTICAL FREQUENCY OF A LASER

Methods and apparatus to control the optical frequency of a laser are disclosed. An apparatus includes: a first laser to emit a first beam of light, the first beam of light to have an adjustable frequency based on an input current; a second laser to emit a second beam of light, the second beam of light to have a substantially fixed frequency; a photodetector to generate a feedback signal indicative of a frequency difference between the first and second beams of light; and logic circuitry to control the input current based on the feedback signal. 1. An apparatus comprising:a first laser to emit a first beam of light, the first beam of light to have an adjustable frequency based on an input current;a second laser to emit a second beam of light, the second beam of light to have a substantially fixed frequency;a photodetector to generate a feedback signal indicative of a frequency difference between the first and second beams of light; andlogic circuitry to control the input current based on the feedback signal.2. The apparatus of claim 1 , further including an optical combiner to combine at least a portion of the first beam of light with the second beam of light claim 1 , the photodetector to generate the feedback signal based on an output of the combiner claim 1 , the feedback signal corresponding to a beat frequency of the combined first and second beams of light.3. The apparatus of claim 2 , wherein the optical combiner is an optical coupler in a monolithic integrated circuit claim 2 , the monolithic integrated circuit including the first laser claim 2 , the second laser claim 2 , the optical coupler claim 2 , and the photodetector.4. The apparatus of claim 2 , wherein the beat frequency is within the radio frequency spectrum.5. The apparatus of claim 2 , wherein the feedback signal generated by the photodetector is to have a feedback frequency corresponding to the beat frequency.6. The apparatus of claim 5 , further including a frequency divider to reduce the ...

HISTOGRAM BASED OPTIMIZATION FOR OPTICAL MODULATION

The present invention is directed to communication systems and methods. In a specific embodiment, the present invention provides an optical receiver that receives a data stream from an optical transmitter. The optical receiver determines a histogram contour parameter using the data stream and inserts the histogram contour parameter into a back-channel data segment, which is then transmitted to the optical transmitter. The optical transmitter changes its data transmission setting based on the histogram contour parameter. There are other embodiments as well. 1. An optical transceiver apparatus comprising:an optical receiver for converting incoming optical signals to incoming electrical signals;a histogram generation module configured to analyze the incoming electrical signals and to generate a histogram characterizing the incoming electrical signals;a control module configured to process the incoming electrical signal and to generate a signal quality value based on the histogram, the signal quality value being calculated using a quadratic fit of the histogram, the signal quality value being associated with a first order coefficient of the quadratic fit;a back-channel insertion module configured to insert the signal quality value to an outgoing data stream; andan optical transmitter for generating output optical signals based on the outgoing data stream.2. The apparatus of wherein further comprising an FEC module configured to encapsulate the back-channel data and a portion of the outgoing data stream into an FEC frame.3. The apparatus of wherein the optical transmitter comprises a laser device.4. The apparatus of wherein the control module is configured to change one or more settings for the laser device based on received back-channel data embedded in the incoming electrical signals.5. The apparatus of wherein the one or more settings include a laser wavelength.6. The apparatus of wherein the optical transmitter comprises a modulator.7. The apparatus of wherein the ...

WAVELENGTH DETERMINATION FOR WIDELY TUNABLE LASERS AND LASER SYSTEMS THEREOF

Methods for wavelength determination of widely tunable lasers and systems thereof may be implemented with solid-state laser based photonic systems based on photonic integrated circuit technology as well as discrete table top systems such as widely-tunable external cavity lasers and systems. The methods allow integrated wavelength control enabling immediate system wavelength calibration without the need for external wavelength monitoring instruments. Wavelength determination is achieved using a monolithic solid-state based optical cavity with a well-defined transmission or reflection function acting as a wavelength etalon. The solid-state etalon may be used with a wavelength shift tracking component, e.g., a non-balanced interferometer, to calibrate the entire laser emission tuning curve within one wavelength sweep. The method is particularly useful for integrated photonic systems based on Vernier-filter mechanism where the starting wavelength is not known a-priori, or for compact widely tunable external cavity lasers eliminating the need for calibration of wavelength via external instruments. 1. A solid-state laser-based device comprising:a solid-state gain medium based widely tunable laser for emitting light;a wavelength shift tracking device for tracking a wavelength shift of the emitted light; anda solid-state based etalon comprising an optical element having at least one of an unambiguous transmission spectrum or an unambiguous reflection spectrum,wherein, during a wavelength sweep of the widely tunable laser, the solid-state based etalon and wavelength shift tracking device are configured to cooperate to provide absolute wavelength determination and control of the widely tunable laser.2. The solid-state laser-based device of claim 1 , wherein during the wavelength sweep claim 1 , the wavelength shift tracking device provides an output of wavelength shift as a function of time claim 1 , and the solid state etalon provides an output of a signal with information ...

Broadband Tunable External-Cavity Laser Using Small Mems Mirror

A Raman pump laser control apparatus comprises a wavelength division multiplexer, a tap coupler, a photoelectric detector, an analogue amplification processing circuit, an analogue-to-digital converter, a fast Raman pump control unit, an digital-analog converter, and a Raman pump laser. The fast Raman pump control unit, after having known anticipated output light power of the Raman pump laser, based on a direct relationship between a current anticipated output light power of the Raman pump laser and input digital quantity that is needed by the digital-analog converter, uses a feedforward control mechanism so that actual output light power of the Raman pump laser fastly approximates the anticipated output light power thereof, and then synchronously combines with a feedback control mechanism so that the actual output light power of the Raman pump laser is precisely locked on the anticipated output light power, thereby achieving fast and precise control of the Raman pump laser.

Polarization stable widely tunable short cavity laser

A tunable source includes a short-cavity laser optimized for performance and reliability in SSOCT imaging systems, spectroscopic detection systems, and other types of detection and sensing systems. A short cavity laser with a large free spectral range cavity, fast tuning response and single transverse, longitudinal and polarization mode operation is disclosed. Methods for obtaining polarization stable operation of the tunable source are presented.

Wavelength tunable laser device and laser module

A wavelength tunable laser device includes: a laser cavity formed of a grating and a reflecting mirror including a ring resonator filter; a gain portion; and a phase adjusting portion. The grating creates a first comb-shaped reflection spectrum. The ring resonator filter includes a ring-shaped waveguide and two arms and creates a second comb-shaped reflection spectrum having peaks of a narrower full width than peaks in the first comb-shaped reflection spectrum at a wavelength interval different from that of the first comb-shaped reflection spectrum. One of the peaks in the first comb-shaped reflection spectrum and one of the peaks in the second comb-shaped reflection spectrum are overlapped on a wavelength axis, and a spacing between cavity modes is narrower than the full width at half maximum of the peaks in the first comb-shaped reflection spectrum.

OPTICAL TRANSMITTER, OPTICAL RECEIVER AND OPTICAL TRANSMISSION METHOD

An optical transmitter includes: a light source configured to generate CW light; a drive signal generator configured to generate a drive signal; an optical modulator configured to modulate the CW light with the drive signal so as to generate a first optical signal; a combiner configured to combine the first optical signal and a second optical signal generated by using another light source; and a detector configured to detect a frequency difference between a frequency of the CW light and a center frequency of the second optical signal. The drive signal generator includes: a mapper configured to generate an electric field information signal based on input data; and a frequency controller configured to modify the electric field information signal based on the frequency difference such that the frequency of the CW light matches the center frequency of the second optical signal to generate the drive signal. 1. An optical transmitter comprising:a light source configured to generate continuous wave light;a drive signal generator configured to generate a drive signal based on input data;an optical modulator configured to modulate the continuous wave light with the drive signal so as to generate a first optical signal;a combiner configured to combine the first optical signal and a second optical signal generated by using another light source that is different from the light source; anda frequency difference detector configured to detect a frequency difference between a frequency of the continuous wave light and a center frequency of the second optical signal, wherein a mapper configured to generate an electric field information signal based on the input data; and', 'a frequency controller configured to modify the electric field information signal based on the frequency difference such that the frequency of the continuous wave light matches the center frequency of the second optical signal so as to generate the drive signal., 'the drive signal generator includes2. The optical ...

LASER DEVICE

The invention relates to a laser device, comprising a laser configured to generate laser light and a laser control module configured to receive at least a portion of the laser light generated by the laser, to generate a control signal and to feed the control signal back to the laser for stabilizing the frequency, wherein the laser control module comprises a tunable frequency discriminating element which is preferably continuously frequency tunable, and where the laser control module is placed outside the laser cavity. 139.-. (canceled)40. A sensor comprising a laser device , comprising:a tunable laser configured to generate laser light and a laser control module configured to receive at least a portion of the laser light generated by the laser to generate a control signal and to feed the control signal back to the laser for stabilizing the frequency,wherein the laser comprises a laser cavity and the laser control module comprises a tunable frequency discriminating element which is preferably continuously frequency tunable, and where the laser control module is placed outside the laser cavity,wherein the laser control module is encapsulated inside a hermetically sealed housing.41. The sensor according claim 40 , wherein the tunable laser operates in a single longitudinal mode42. The sensor according to claim 40 , wherein the tunable laser is a fiber laser claim 40 , a diode laser or a solid-state laser43. The sensor according to claim 40 , wherein the frequency discriminating element comprises solid silica44. The sensor according to claim 40 , wherein the laser control module is fiber coupled to the tunable laser.45. The sensor according to claim 40 , wherein the laser control module is temperature controlled46. The sensor according to claim 40 , wherein the frequency discriminating element is an interferometer.47. The sensor according to claim 46 , wherein the interferometer is a Fabry-Perot interferometer.48. The sensor according to claim 46 , wherein the ...

WAVELENGTH-TUNABLE LASER APPARATUS HAVING WAVELENGTH MEASURING FUNCTION

The present invention relates to a wavelength-tunable laser apparatus which can measure a wavelength in a wavelength-tunable laser diode package structure for dense wavelength division multiplexing (DWDM) having a transistor outline (TO) type appearance. The wavelength-tunable laser apparatus of the present invention is a TO-can type wavelength-tunable laser apparatus comprising: a laser diode chip for emitting a laser beam; a collimator lens for collimating the laser beam; a wavelength-selective filter through which the selected wavelength passes; and a reflecting mirror having an inclined reflective surface, wherein the laser beam is split into a beam which is emitted from the laser diode chip (), collimated by the collimator lens () and emitted through a 45-degree reflective mirror () to the outside of a TO-can type package, and a beam which passes through the 45-degree reflective mirror (), the beam passing through the 45-degree reflective mirror () is split into at least two branched beams, a first photodiode () is arranged on the path of one branched beam so as to monitor the beam, and wavelength-selective filters () having variable transmittance according to the wavelengths and a second photodiode () are further arranged on the path of the other branched beam. 1. A wavelength-tunable laser apparatus which is a TO-can type wavelength-tunable laser apparatus comprisinga laser diode chip for emitting a laser beam,a collimator lens for collimating the laser beam,a wavelength-selective filter through which the selected wavelength passes, anda reflecting mirror having an inclined reflective surface,{'b': 100', '200', '300', '300', '300', '510', '400', '600', '520, 'wherein the laser beam is split into a beam which is emitted from the laser diode chip , collimated by the collimator lens and emitted through a 45-degree reflective mirror to the outside of a TO-can type package, and a beam which passes through the 45-degree reflective mirror , the beam passing through ...

Noise detection, diagnostics, and control of modelocked lasers

The present invention features a laser based system configured with a noise detection unit. The system includes a mode-locked oscillator. A noise detection unit includes at least one optical detector that monitors optical pulses generated by the mode-locked oscillator and produces an electrical signal in response to the optical pulses. The noise detection unit includes a first filter to transmit signal power over a signal bandwidth which includes the mode-locked laser repetition frequency, frep. The noise detection unit may include one or more filters to transmit power over a noise bandwidth that substantially excludes repetition frequency, frep. Non-linear signal processing equipment is utilized to generate one or more signals representative of the power in the signal bandwidth relative to the power in the noise bandwidth. The system includes a controller operable to generate a signal for controlling the laser based system based on the relative power.

Semiconductor laser driving circuit

The semiconductor laser driving circuit that controls an overshoot on modulation includes a semiconductor laser, of which anode is connected to a power source, that emits the laser light that is modulated by an external modulation input signal, an impedance element connected to a cathode of the laser device, an impedance element connected to the anode, and a collector of a transistor Q1, connected to the impedance element; a collector of a transistor Q2, connected to the other end of the impedance element, a differential pair circuit to which emitters of Q1, Q2 are connected; an electric current source iMOD connected to the emitters of Q1, Q2; and a differential driver that generates a differential voltage (vb1−vb2) that controls Q1, Q2 by driving Q1 by the external modulation input signal, wherein the differential driver controls the differential voltage so that the amplitude of the overshoot of the electric current, which flows in the laser when the output of the laser is at a high-level.

Method and apparatus for coherence enhancement of sweep velocity locked lasers via all-electronic upconversion

The present disclosure provides methods and apparatus to improve the dynamic coherent length of a sweep velocity-locked laser pulse generator (SV-LLPG) in an all-electronic fashion. A digital SV-LLPG is disclosed with two operation modes, i.e., unidirectional and bidirectional sweep modes; self-adaptive and time-dependent loop parameters (gain and location of poles/zeros); and, self-adaptive initial input curve. High frequency locking architectures, both single-side band (SSB) modulation method and direct phase measurement method, are provided to suppress the linewidth, or improve the coherent length, of the swept laser. A combination of high and low frequency locking, or a combination of multiple architectures disclosed in this invention, is utilized to achieve a higher level of linewidth reduction. The enhanced laser coherence extends the measurement range by at least one order of magnitude for applications including frequency-modulated continuous wave (FMCW) light detection and ranging (LiDAR) and optical fiber distributed sensing applications.

LASER WAVELENGTH STABILIZATION APPARATUS

A wavelength sensor for wavelength stabilization of a laser beam includes an etalon placed in the laser beam and tilted with respect to the laser beam. Reflected beams from the etalon form an interference pattern on a segmented photodetector having two detector segments. Output signals from the two detector segments are used to derive an error signal for a closed control loop to effect the wavelength stabilization. 1. A wavelength sensing apparatus for a laser beam comprising:a non-birefringent etalon having first and second parallel surfaces, the etalon located in the laser beam; anda segmented photodetector having first and second detector segments, the etalon being tilted with respect to the laser beam such that first and second reflected beams from respectively the first and second parallel surfaces are directed onto the segmented photodetector to form an interference pattern, the segmented photodetector located at a far-field distance of the first and second reflected beams, the first and second detector segments producing respectively first and second output signals, changes in the first and second output signals corresponding to changes in the wavelength of the laser beam.2. The apparatus of claim 1 , further including a signal processor receiving the first and second output signals claim 1 , and deriving therefrom an error signal that is representative of a phase relationship between the first and second reflected beams.3. The apparatus of claim 2 , wherein the error signal is derived by dividing a difference between the first and second output signals by a total of the first and second output signals.4. The apparatus of claim 3 , wherein the error signal is zero when the first and second reflected beams are completely out-of-phase.5. The apparatus of claim 1 , wherein the laser beam is an output beam of a laser.6. The apparatus of claim 1 , wherein the laser beam is circulating within a laser resonator.7. The apparatus of claim 1 , wherein the interference ...

SYSTEM AND METHOD FOR CONTROLLING COLLOCATED MULTIPLE WAVELENGTH TUNED LASERS

Systems and methods are disclosed herein for controlling laser beams for a plurality of collocated laser assemblies. The laser beams are optimized by controlling outputs of a primary power source (current for generating a laser beam) and a secondary power source (heating device) for each of the respective laser assemblies. The states of the power supply may be cycled and modulated to provide optimal performance. 1detecting at a controller, a plurality of proximal lasers;determining a thermal effect caused by a first of the plurality of lasers on a second of the plurality of proximal lasers; andcontrolling an output of a primary power source.. A method for controlling a plurality of collocated lasers, the method comprising: This application is a continuation of U.S. patent application Ser. No. 14/456,738, filed Aug. 11, 2014, and claims priority to U.S. Provisional Application Ser. No. 61/889,320 filed Oct. 10, 2013, entitled “Semiconductor Laser Thermal Control Method for Collocated Multiple Wavelength Tuned Lasers,” the entire contents of which are hereby incorporated by reference.Semiconductor laser wavelength can vary due to changes in the device temperature. Semiconductor lasers such as distributed feedback (DFB) and/or ridge waveguide lasers often include electronic means to control the intensity and wavelength of the laser by applying a differential voltage to the positive and negative terminal and varying the laser current. By gradually increasing the applied current, the laser will operate with higher optical intensity and increasing wavelength. Only a portion of the applied energy is converted to optical energy while the remaining energy is converted to heat. Various control methods are employed to mitigate thermal variation to maintain desired nominal laser wavelength.One method used to control wavelength in semiconductor lasers is to apply a secondary current to an electrode in proximity to the laser device (e.g., with a heater) to tune the wavelength to ...

Laser Driver Modulation and Bias Control Scheme

Systems and methods are provided for generating an accurate, stable measurement for a laser bias current. The average current and the extinction ratio are controlled using a dual control loop. The transfer function between the laser and a monitor photo diode (MPD) is characterized. A laser driver control module predicts the average power that will be measured using the MPD relative to the data being transmitted, and this information is used to control a laser driver.

SINGLE LONGITUDINAL MODE LASER DIODE SYSTEM

A semiconductor laser diode system may include a single longitudinal mode laser diode and a feedback system that monitors and controls the emission characteristics of the laser diode. The laser diode may include a gain medium and an optical feedback device. The feedback system may include a wavelength discriminator, an optical detector, a microprocessor, and a laser controller. Such a semiconductor laser diode system may be used to produce laser light having coherence length, wavelength precision, and wavelength stability that is equivalent to that of a gas laser. Accordingly, such a semiconductor laser diode system may be used in place of a traditional gas laser. 1. A semiconductor laser diode system , comprising:a semiconductor laser source having a laser cavity;an optical feedback device, wherein the optical feedback device is a three-dimensional optical element having a Bragg grating recorded therein, and wherein the Bragg grating causes a narrowband portion of radiation emitted from the laser source to be fed back into the laser cavity, the optical feedback device being configured to cause the laser diode to achieve single longitudinal mode at a desired wavelength; anda feedback system that monitors emission characteristics of the laser diode, the feedback system comprising a processor that is configured to adjust one or more control characteristics of the laser diode to cause the laser diode to achieve and maintain a single longitudinal mode condition using only output power characteristics of the laser diode.2. The semiconductor laser diode system of claim 1 , wherein the Bragg grating causes the narrowband portion of the radiation emitted from the laser source to be fed back into the laser cavity as seed light at the desired wavelength.3. The semiconductor laser diode system of claim 1 , wherein the Bragg grating causes the narrowband portion of the radiation emitted from the laser source to be reflected back into the laser cavity as seed light at the ...

PULSE-WIDTH MODULATION LIGHT SOURCE DRIVE AND METHOD

A pulse-width modulation (PWM) light source drive for driving a light source is provided that includes a microcontroller, a modulation element, a voltage regulator, and a light detector. The microcontroller is configured to generate a PWM signal and an inverse PWM signal. The modulation element is configured to generate a drive signal based on the PWM signal. The light source is configured to be driven by the drive signal. The voltage regulator is configured to generate an output drive voltage for the light source. The light detector is configured to detect light energy emitted by the light source, to generate an optical power feedback signal based on the detected light energy, and to provide the optical power feedback signal to the voltage regulator during a laser-on driving interval. The microcontroller is configured to provide the inverse PWM signal to the voltage regulator during a laser-off driving interval. The voltage regulator is configured to adjust the output drive voltage based on the optical power feedback signal during the laser-on driving interval and based on the inverse PWM signal during the laser-off driving interval. 1. A pulse-width modulation (PWM) light source drive for driving a light source , comprising:a microcontroller configured to generate a PWM signal and an inverse PWM signal;a modulation element configured to generate a drive signal based on the PWM signal, wherein the light source is configured to be driven by the drive signal;a voltage regulator configured to generate an output drive voltage for the light source; anda light detector configured to detect light energy emitted by the light source, to generate an optical power feedback signal based on the detected light energy, and to provide the optical power feedback signal to the voltage regulator during a laser-on driving interval,wherein the microcontroller is further configured to provide the inverse PWM signal to the voltage regulator during a laser-off driving interval, andwherein ...

Method of Estimating a Condition Parameter of a Laser Diode with an Associated Photodiode, Apparatus for Monitoring the Operation of Such Laser Diode and Particular Sensor Apparatus

The present invention provides a method for estimating a condition parameter of a laser diode having an associated photodiode, to an apparatus for monitoring the operation of such a laser diode, and to a particle sensor apparatus. The photodiode (PD) is operable together with the laser diode (LD), wherein it detects the light (LS) of the laser diode (LD) and converts it into an electrical current, and is thermally coupled to the laser diode (LD). The at least one condition parameter is estimated during the operation of the laser diode (LD) and the estimation is based on current measurements and/or voltage measurements at the laser diode (LD) and/or at the photodiode (PD). 2. The method as claimed in claim 1 , wherein the laser diode having the associated photodiode is a laser diode having an integrated photodiode claim 1 , in particular a VCSEL (vertical-cavity surface-emitting laser) having an integrated photodiode.3. The method as claimed in claim 1 , wherein the laser diode temperature TLD is estimated as the condition parameter of the laser diode by way ofdetermining the slope PDSlope of the photodiode characteristic at the laser diode temperature TLD to be determined for at least two different values of the laser diode current ILD using measurements of the photodiode current IPD, andby basing the estimation of the laser diode temperature TLD on a previously determined relationship between the slope PDSlope of the photodiode characteristic and the laser diode temperature TLD.4. The method as claimed in claim 1 , wherein the laser diode temperature TLD is estimated as the condition parameter of the laser diode by way ofcapturing the laser diode voltage ULD for at least one specified laser diode current ILDV at the laser diode temperature TLD that is to be estimated, andbasing the estimation of the laser diode temperature TLD on a previously determined relationship between the predetermined laser diode current ILDV, the laser diode voltage ULD, and the laser diode ...

STABILIZED LIDAR SYSTEM AND METHOD FOR STABILIZATION

A stabilized LiDAR system and a method for stabilization. The LiDAR system includes a laser, the laser being designed for emission of monochromatic LiDAR radiation within a wavelength working range; a thermocouple element configured to set the working temperature of the laser; a means for evaluation, designed to determine, from the radiation emitted by the laser, a measure for the deviation from an actual wavelength of the radiation to a setpoint wavelength within the wavelength working range of the laser; and a means for regulation, designed to control the thermocouple element on the basis of the measure of deviation determined by the means for evaluation, in such a way that the working temperature of the laser is set to a value, at which the emitted monochromatic LiDAR radiation corresponds to the setpoint radiation. 1. A LiDAR system , comprising:a laser configured to emit monochromatic LiDAR radiation within a wavelength working range;a thermocouple element configured to set a working temperature of the laser;an evaluation device configured to determine, from the radiation emitted by the laser, a measure for a deviation from an actual wavelength of the radiation to a setpoint wavelength within the wavelength working range of the laser; anda regulator configured to control the thermocouple element on based on the measure of deviation determined by the evaluation device in such a way that the working temperature of the laser is set to a value at which the emitted monochromatic LiDAR radiation corresponds to the setpoint wavelength.2. The LiDAR system as recited in claim 1 , wherein the evaluation device includes:two monitor diodes configured to determine an intensity of a diverted portion of the LiDAR radiation emitted by the laser, the radiation passing through an optical filter element before striking the monitor diodes, which, starting from the setpoint wavelength within the wavelength working range of the laser, have passbands in different spectral directions, ...

Optical Transmitter and Light Intensity Monitoring Method

The present invention provides an optical transmitter and a light intensity monitoring method that provide reliable APC feedback for a semiconductor laser equipped with an SOA. The optical transmitter includes an SOA integrated EA-DFB having a DFB laser, an EA modulator connected to the DFB laser, and an SOA connected to the EA modulator. In the structure of the optical transmitter, a light detector part is disposed forward of the output end side of an SOA part. The light detector part changes part of an output light beam from the SOA part into an electric current and detects light, while guiding the remaining part of the output light beam to a waveguide. With the light detector part disposed forward for the SOA part, it is possible to feed back the output result from the SOA part. Hence, good APC is possible. 1. An optical transmitter comprising:an SOA integrated EA-DFB including a DFB laser, an EA modulator connected to the DFB laser, and an SOA connected to the EA modulator;a first light detector for monitoring a signal light beam emitted from the SOA of the SOA integrated EA-DFB; anda drive device connected to the DFB laser and the SOA by a single control terminal, for controlling a drive current in accordance with light intensity detected by the first light detector.2. The optical transmitter according to claim 1 , further comprising a second light detector for monitoring a light beam emitted from the DFB laser claim 1 , the light beam being monitored without passing through the SOA.3. The optical transmitter according to claim 2 , wherein the second light detector is disposed to be connected to an end surface of the DFB laser opposite from an end surface thereof connected to the EA modulator.4. The optical transmitter according to claim 2 , wherein the second light detector is disposed between the DFB laser and the SOA of the SOA integrated EA-DFB.5. (canceled)6. A light intensity monitoring method in an SOA integrated EA-DFB including a DFB laser claim 2 , an ...

Stable Linewidth Narrowing Of A Coherent Comb Laser

A technique for narrowing a linewidth of a plurality of lines of a coherent comb laser (CCL) concurrently comprises providing a mode-locked semiconductor coherent comb laser (CCL) adapted to output of at least 4 mode-locked lines; tapping a fraction of a power from the CCL from the laser cavity to form a tapped beam; propagating the tapped beam to an attenuator to produce an attenuated beam; and reinserting the attenuated beam into the laser cavity, where the reinserted beam has a power less than 10% of a power of the tapped beam. The reinsertion allows the CCL to be operated to output the mode-locked lines, each with a linewidth of less than 80% of the original linewidth. By propagating the tapped and attenuated beams on a solid waveguide, and ensuring that the secondary cavity is polarization maintaining, improved stability of the linewidth narrowing is ensured. 1. A method for narrowing a linewidth of a coherent comb laser (CCL) comprising:providing a mode-locked semiconductor coherent comb laser (CCL) with a laser cavity defined by an active gain material in a waveguide between two facets, the CCL adapted to output of at least 4 mode-locked lines, each with an original linewidth of less than 100 MHz;tapping a fraction of a power from the CCL from the laser cavity to form a tapped beam;propagating the tapped beam to an attenuator to produce an attenuated beam and propagating the attenuated beam back to the laser cavity; on a solid waveguide; andreinserting the attenuated beam into the laser cavity, where the reinserted beam has a power less than 10% of a power of the tapped beam,where the reinsertion allows the CCL to be operated to output the mode-locked lines, each with a linewidth of less than 80% of the original linewidth, andan optical path between tapping and reinsertion is polarization maintaining.2. The method of where the provided mode-locked semiconductor CCL:is adapted to output at least 10 mode-locked lines;is adapted to output at least 4 mode-locked ...

Stable Linewidth Narrowing Of A Coherent Comb Laser

A technique for narrowing a linewidth of a plurality of lines of a coherent comb laser (CCL) concurrently comprises providing a mode-locked semiconductor coherent comb laser (CCL) adapted to output of at least 4 mode-locked lines; tapping a fraction of a power from the CCL from the laser cavity to form a tapped beam; propagating the tapped beam to an attenuator to produce an attenuated beam; and reinserting the attenuated beam into the laser cavity, where the reinserted beam has a power less than 10% of a power of the tapped beam. The reinsertion allows the CCL to be operated to output the mode-locked lines, each with a linewidth of less than 80% of the original linewidth. By propagating the tapped and attenuated beams on a solid waveguide, and ensuring that the secondary cavity is polarization maintaining, improved stability of the linewidth narrowing is ensured.

OFF QUADRATURE MACH-ZEHNDER MODULATOR BIASING

The present invention relates to telecommunication techniques and integrated circuit (IC) devices. More specifically, embodiments of the present invention provide an off-quadrature modulation system. Once an off-quadrature modulation position is determined, a ratio between DC power transfer amplitude and dither tone amplitude for a modulator is as a control loop target to stabilize off-quadrature modulation. DC power transfer amplitude is obtained by measuring and sampling the output of an optical modulator. Dither tone amplitude is obtained by measuring and sampling the modulator output and performing calculation using the optical modulator output values and corresponding dither tone values. There are other embodiments as well. 1. An off-quadrature biased optical modulation system comprising:a driver module configured to output a driving signal, the driving signal including a dither tone component;a memory for storing a lookup table and a predetermined ratio, the lookup table comprising an array of n sine values based on a plurality of n dither frequencies, the lookup table further comprising an array of n cosine values based on the plurality of n dither frequencies;a modulator configured to generate a dump signal using at least the driving signal;an analog to digital converter (ADC) configured to sample the dump signal to generate n dump samples;a microcontroller unit being configured to calculate a measured ratio based a first sum and the second sum, the first sum being based on the n dump samples, the second sum being based on the n dump samples and the array of n cosine values and the array of n sine values; anda control module being configured to adjust one or more operating parameters to match the measured ratio to a predetermined ratio.2. The system of wherein the n wherein the predetermined ratio is associated with a set of optimized operating parameters.3. The system of further comprising a light source.4. The system of wherein the modulator is configured ...

SEMICONDUCTOR RADIATION SOURCE

A semiconductor radiation source includes at least one semiconductor chip that generates radiation; a controller with one or more switching elements configured for pulsed operation of the semiconductor chip; and at least one capacitor body, wherein the semiconductor chip directly electrically connects in a planar manner to the capacitor body, the controller electrically connects to a side of the semiconductor chip opposite the capacitor body, and the controller, the capacitor body and the semiconductor chip are stacked on top of each other so that the capacitor body is located between the control unit and the semiconductor chip. 115-. (canceled)16. A semiconductor radiation source comprising:at least one semiconductor chip that generates radiation;a controller with one or more switching elements configured for pulsed operation of the semiconductor chip; andat least one capacitor body,whereinthe semiconductor chip directly electrically connects in a planar manner to the capacitor body,the controller electrically connects to a side of the semiconductor chip opposite the capacitor body, andthe controller, the capacitor body and the semiconductor chip are stacked on top of each other so that the capacitor body is located between the controller and the semiconductor chip.17. The semiconductor radiation source according to claim 16 ,wherein the semiconductor chip is a semiconductor laser chip, andthe capacitor body has a larger base area than the semiconductor chip and an electrical contact area between the semiconductor chip and the capacitor body is at least 50% of the base area.18. The semiconductor radiation source according to claim 16 , wherein the semiconductor chip and the capacitor body have equal lateral dimensions along each direction with a tolerance of at most 10% claim 16 , and an electrical contact area between the semiconductor chip and the capacitor body is at least 80% of a base surface of the semiconductor chip.19. The semiconductor radiation source ...

Method and Apparatus for Monitoring the Optical Output Power of a Laser Diode with an Associated Photodiode and Particle Sensor Device

The present invention provides methods and an apparatus for monitoring the optical output power of a laser diode (LD) having an associated photodiode (PD), and a particle sensor apparatus. The photodiode (PD) is operable together with the laser diode (LD), wherein it detects the light (LS) of the laser diode (LD) and converts it into an electrical current, and is thermally coupled to the laser diode (LD). Monitoring of the optical output power P is effected during the operation of the laser diode (LD) and is based on current measurements and/or voltage measurements at the laser diode (LD) and at the photodiode (PD). 1. A method for monitoring the optical output power P of at least one laser diode , wherein at least one photodiode is associated with the laser diode ,which is operable together with the laser diode,which detects the light of the laser diode and converts it into an electrical current IPD, andwhich is thermally coupled to the laser diode,wherein the optical output power P is monitored during the operation of the laser diode and the monitoring is based on current measurements and/or voltage measurements at the laser diode and at the photodiode.2. The method as claimed in claim 1 , wherein the laser diode (D) having the associated photodiode is a laser diode having an integrated photodiode claim 1 , in particular a VCSEL (vertical-cavity surface-emitting laser) having an integrated photodiode.3. The method as claimed in claim 1 , whereindetermining a respective instantaneous photodiode characteristic by way of measurements of the photodiode current IPD in dependence on the laser diode current ILD,determining the instantaneous threshold current Ith of the laser diode from the respective instantaneous photodiode characteristic,determining the slope PDSlope of the instantaneous photodiode characteristic for a laser diode current region within which the laser diode is in laser operation, andcapturing the laser diode voltage ULD for at least one specified laser ...

LIGHT SOURCE DEVICE

A light source device includes at least one first wiring, a plurality of second wirings, a plurality of light emitting elements each having a lower-surface-side electrode connected to a respective one of the at least one first wiring, a plurality of protective elements each having a lower-surface-side electrode connected to a respective one of the plurality of second wirings each corresponding to a respective one of the plurality of light emitting elements, each of the plurality of protective elements connected to a respective one of the plurality of light emitting elements, a plurality of first wirings each connecting an upper-surface-side electrode of each of the plurality of light emitting elements and a respective one of the plurality of second wirings, a plurality of second wires each connecting the upper-surface-side electrodes of two adjacent ones of the protective elements; and a plurality of third wires each connecting an upper-surface-side electrode of a respective one of the plurality of protective elements and a corresponding one of the at least one first wiring. The upper-surface-side electrodes of the plurality of light emitting elements and the upper-surface-side electrodes of the plurality of protective elements are of a same polarity, and the plurality of first wires are disposed below the plurality of second wires. 1. A light source device comprising:at least one first wiring;a plurality of second wirings;a plurality of light emitting elements each having a lower-surface-side electrode connected to a respective one of the at least one first wiring;a plurality of protective elements each having a lower-surface-side electrode connected to a respective one of the plurality of second wirings each corresponding to a respective one of the plurality of light emitting elements, each of the plurality of protective elements connected to a respective one of the plurality of light emitting elements;a plurality of first wirings each connecting an upper-surface- ...

TUNABLE LASER AND OPTICAL MODULE

A tunable laser includes a housing having a sealable accommodating cavity, an optical interface and an electrical interface disposed on the housing, a tunable semiconductor laser apparatus, a splitter component, and a photodetector. The tunable semiconductor laser apparatus is disposed in the accommodating cavity for emitting an optical signal whose wavelength is tunable. An electrical signal inputted through the electrical interface controls the tunable semiconductor laser apparatus to emit the optical signal. The optical signal is outputted through the optical interface. The splitter component and the photodetector are disposed outside the housing. The optical signal is split into at least two beams of light by the splitter component after the optical signal is outputted through the optical interface. The photodetector is configured to receive one of the beams of light to monitor the optical signal emitted by the tunable semiconductor laser apparatus. 1. A tunable laser , comprises:a housing having a sealable accommodating cavity;an optical interface disposed at one end of the housing;an electrical interface disposed at another end or a side of the housing;a tunable semiconductor laser apparatus disposed in the accommodating cavity and configured to emit an optical signal whose wavelength is tunable, an electrical signal inputted through the electrical interface controlling the tunable semiconductor laser apparatus to emit the optical signal, the optical signal being outputted through the optical interface;a splitter component disposed outside the housing and configured to split the optical signal outputted through the optical interface into at least two beams of light; anda photodetector disposed outside the housing and configured to receive one of the beams of light to monitor the optical signal emitted by the tunable semiconductor laser apparatus.2. The tunable laser of claim 1 , wherein the tunable laser further comprises:a circuit board disposed outside the ...

Wavelength monitor and optical module

A wavelength monitor monitors wavelengths of laser beams emitted from a laser source and transmitted through a collimating lens. The wavelength monitor comprises an etalon that serves as an optical filter, and an optical detector. The etalon has a transmittance that is periodic with respect to a frequency, and is disposed such that a pair of collimated beams, emitted through a pair of emitting ports of the laser source and then transmitted through the collimating lens, is incident on the optical filter at symmetrically positive and negative angles. The optical detector receives the pair of collimated beams transmitted through the etalon, and detects the intensities of the pair of collimated beams.

OPTICAL TRANSMISSION APPARATUS, OPTICAL COMMUNICATION SYSTEM AND OPTICAL COMMUNICATION METHOD

To reduce deterioration of signal quality, an optical transmission apparatus comprises a transmission means for outputting an optical signal, and a multiplexing device for outputting a wavelength multiplexed optical signal including the optical signal inputted from the transmission means, wherein the multiplexing device includes an input port that is set to transmit a first wavelength band of the optical signal inputted from the transmission means, an intensity adjustment unit that can adjust an amount of optical attenuation for each predetermined wavelength band, and adjusts the amount of optical attenuation of an edge band of the first wavelength band of the optical signal transmitted through the input port to be smaller than the amount of optical attenuation of a central band of the first wavelength band, and an output port that outputs a wavelength multiplexed optical signal including the optical signal with the adjusted amount of optical attenuation. 1. An optical transmission apparatus , comprising:a transmitter configured to output an optical signal; anda multiplexer configured to output a wavelength multiplexed optical signal including the optical signal being input from the transmitter, wherein an input portion being set in such a way as to allow a first wavelength band of the optical signal to pass through, the optical signal being input from the transmitter;', 'an intensity adjuster, being capable of adjusting an optical attenuation amount per predetermined wavelength band unit, configured to adjust the optical attenuation amount in an edge band of the first wavelength band of the optical signal passing through the input portion to be smaller than the optical attenuation amount in a center band of the first wavelength band; and', 'an output portion configured to output the wavelength multiplexed optical signal including the optical signal having the optical attenuation amount being adjusted., 'the multiplexer includes2. The optical transmission apparatus ...

CIRCUITRY AND METHOD FOR DRIVING LASER WITH TEMPERATURE COMPENSATION

A temperature-compensated laser driving circuit for driving a laser component is provided. The temperature-compensated laser driving circuit includes: a temperature compensation circuit, configured to generate a second current based on a first current and a temperature-independent current; and a modulation current generating circuit, configured to generate a modulation current based on the second current, and calibrate optical power output of the laser component based on the modulation current. The first current is proportional to the absolute temperature. The second current and the first current have a slope relative to the absolute temperature respectively, and the slope of the second current relative to the absolute temperature is larger than of the slope of the first current relative to the absolute temperature. 1. A temperature-compensated laser driving circuit , for driving a laser component , comprising:a temperature compensation circuit, configured to generate a second current based on a first current and a temperature-independent current; anda modulation current generating circuit, configured to generate a modulation current based on the second current, and calibrate optical power output of the laser component based on the modulation current;wherein the first current is proportional to the absolute temperature;wherein the second current and the first current have a slope relative to the absolute temperature respectively, and the slope of the second current relative to the absolute temperature is larger than the slope of the first current relative to the absolute temperature.2. The temperature-compensated laser driving circuit as claimed in claim 1 , further comprising a bias current generating circuit claim 1 , configured to generate a bias current flowing through the laser component.3. The temperature-compensated laser driving circuit as claimed in claim 1 , wherein the laser component is a vertical-cavity surface-emitting laser component for use in an ...

Monitoring a multiplexed laser array in an optical communication system

Individual channels of a multiplexed laser array in a multi-channel optical transmitter are monitored at an output of an optical multiplexer. The monitoring may be used to confirm proper operation of each of the channels in the multiplexed laser array and/or to perform wavelength locking on each of the channels. Monitoring at the output of the optical multiplexer avoids the use of multiple photodetectors coupled directly to multiple lasers in the multiplexed laser array. The multiplexed laser array generally includes a plurality of laser emitters optically coupled to an optical multiplexer such as an arrayed waveguide grating (AWG). An optical transmitter with a monitored multiplexed laser array may be used, for example, in an optical line terminal (OLT) in a wavelength division multiplexed (WDM) passive optical network (PON) or in any other type of WDM optical communication system capable of transmitting optical signals on multiple channel wavelengths.

REPEATER, EXCITATION LIGHT SUPPLY DEVICE USED FOR THE SAME, AND EXCITATION LIGHT SUPPLY METHOD

Even when some light emitting elements among the plurality of light emitting elements fail, a repeater, can be continuously operated. Means for solving the problems A light source unit which includes a plurality of pumping light source modules (to ) which include light emitting elements (to ) for emitting an excitation light and monitor elements (to ) for monitoring the excitation lights of the light emitting elements (to ), respectively, a distribution unit which combines the excitation lights from the plurality of pumping light source modules (to ) and distributes it, and a control unit which supplies a drive current flowing serially through the plurality of light emitting elements (to ) in a plurality of excitation modules (to ) are included. 1. An excitation light supply device which supplies an excitation light , comprising:a light source unit which includes a plurality of excitation light source modules, each of which includes a light emitting element for emitting the excitation light and a monitor element for monitoring the excitation light of the light emitting element;a distribution unit which combines the excitation lights from the plurality of excitation light source modules and distributes the combined excitation lights; anda control unit which supplies a drive current flowing serially through the plurality of light emitting elements in a plurality of excitation modules.2. The excitation light supply device according to claim 1 , whereinthe control unit comprises:a control circuit which detects an output signal of the monitor element, obtains a sum of the output signals as a monitor signal, generates a drive signal by which a level of the monitor signal is made equal to a reference value set in advance and outputs the drive signal; anda drive circuit which outputs the drive current to the light source unit based on the drive signal.3. The excitation light supply device according to claim 2 , whereinthe control circuit monitors whether or not a no signal ...

OPTICAL TRANSMISSION DEVICE AND OPTICAL TRANSMISSION METHOD

To generate, in an optical transmission device, a response signal corresponding to executed control even when said optical transmission device does not comprise one or both of a main signal photoelectric conversion function and a main signal optical amplification function, an optical transmission device comprises: an extraction unit that outputs, from a first optical signal including a main signal and a control signal, a signal including control information included in the control signal; a control unit that executes control on the basis of the control information; and a response signal output unit that outputs, according to the control, a response signal in a wavelength band different from the main signal. 1. An optical transmission device comprising:an extraction circuit configured to output a signal from a first optical signal including a main signal and a control signal, the signal including control information included in the control signal;a control circuit configured to execute control, based on the control information; anda response signal output circuit configured to output a response signal in a wavelength band different from a wavelength band of the main signal, according to the control.2. The optical transmission device according to claim 1 , wherein the response signal is generated when the control is executed.3. The optical transmission device according to claim 1 , wherein the response signal includes information on the control.4. The optical transmission device according to claim 1 , wherein the control circuit instructs the response signal output circuit to generate the response signal every time the control is executed.5. The optical transmission device according to claim 1 , wherein execution of the control is output of a control command indicating a content of the control with respect to a function block being a target for the control.6. The optical transmission device according to claim 5 , wherein the control command is output by changing a ...

LASER LIGHT SOURCE DEVICE AND METHOD OF CONTROLLING SAME

An object is to provide a technology capable of suppressing life deterioration of a laser light source device. A laser light source device includes a laser bank having a plurality of semiconductor laser elements, a drive part for applying an electric current to the plurality of semiconductor laser elements of the laser bank, a light intensity detection part for detecting light intensity output from the laser bank, a temperature detection part for detecting a temperature of the laser bank, and a control part for determining an electric current limit value based on the detected temperature, and for controlling the electric current of the drive part based on the detected light intensity and the electric current limit value. 1. A laser light source device comprising:a laser bank having a plurality of semiconductor laser elements;a drive part for applying an electric current to the plurality of semiconductor laser elements of the laser bank;a light intensity detection part for detecting light intensity output from the laser bank;a temperature detection part for detecting a temperature of the laser bank; anda control part for determining an electric current limit value being a limit value of the electric current of the drive part based on the temperature detected by the temperature detection part, and for controlling the electric current of the drive part based on the light intensity detected by the light intensity detection part and the electric current limit value, whereina first temperature range and a second temperature range that is higher than the first temperature range are defined for the temperature of the laser bank, andthe electric current limit value comprises an electric current upper limit value for preventing COD deterioration of the plurality of semiconductor laser elements in the first temperature range, and an electric current upper limit value for preventing COD deterioration and gentle thermal deterioration of the plurality of semiconductor laser ...

METHOD TO TUNE EMISSION WAVELENGTH OF WAVELENGTH TUNABLE LASER APPARATUS AND LASER APPARATUS

A method to tune an emission wavelength of a wavelength tunable laser apparatus is disclosed. The laser apparatus implements, in addition to a wavelength tunable laser diode (t-LD) integrating with a semiconductor optical amplifier (SOA), a wavelength monitor including an etalon filter. The current emission wavelength is determined by a ratio of the magnitude of a filtered beam passing the etalon filter to a raw beam not passing the etalon filter. The method first sets the SOA in an absorbing mode to sense stray component disturbing the wavelength monitor, then correct the ratio of the beams by subtracting the contribution from the stray component. 1. A method to tune an emission wavelength of a laser apparatus that includes a wavelength tunable laser diode (t-LD) integrating a laser diode (LD) with a semiconductor optical amplifier (SOA) , and a wavelength monitor to sense the emission wavelength of the t-LD , the wavelength monitor disposed in one of a front side and a rear side of the t-LD , the wavelength monitor including an optical filter , a first photodiode (PD) to sense a raw beam not transmitting through the optical filter , and a second PD to sense a filtered beam split from the raw beam and transmitting through the optical filter , the method comprising steps of:evaluating a first stray component and a second stray component by the first PD and the second PD, respectively, the first stray component and the second stray component originating to an optical beam output from another of the front side and the rear side not disposing the wavelength monitor;sensing the raw beam and the filtered beam by the first PD and the second PD, respectively; andcalculating a ratio of the filtered beam subtracted with the second stray component to the raw beam subtracted with the first stray component,wherein the SOA is integrated in the front side of the t-LD and the wavelength monitor is disposed in the front side of the t-LD, and setting the SOA in an absorbing mode;', ...

TRANSISTOR OUTLINE HEADER FOR HIGH-SPEED DATA TRANSMISSION OF OPTOELECTRONIC APPLICATIONS

A header for opto-electronic applications is provided. The header includes a header base with a back face, a front face, and opening that extends from the back face through the base to the front face. The opening accommodates an electrically isolated pin through the opening. A pedestal is arranged at the front face and is below a center of the opening. The pedestal has a mounting face and a free face, which opposes the mounting face. The pedestal further includes an upper surface for mounting and carrying a pedestal submount. The mounting face is fixedly attached to the front face with an electrically conductive material that is at least partially arranged between the front face and the mounting face. An electrically isolating material is arranged in the opening between the base and the pin to electrically isolate the pin from the base.

Driver circuitry and systems for high current laser diode arrays

Apparatuses, methods, and systems are disclosed to drive pumping laser diode arrays. In implementations, an integrated system can be constructed to in a compact, efficient and cost-effective manner and to meet the needs of driving laser diode arrays in various diode pumped solid state laser applications. The disclosed implementations include individual laser diode drivers or pulsers, methods of communicating with laser diode drivers, and methods of controlling the pulse shape of each laser diode driver.

Integrated wavelength locker

Described are various configurations of integrated wavelength lockers including asymmetric Mach-Zehnder interferometers (AMZIs) and associated detectors. Various embodiments provide improved wavelength-locking accuracy by using an active tuning element in the AMZI to achieve an operational position with high locking sensitivity, a coherent receiver to reduce the frequency-dependence of the locking sensitivity, and/or a temperature sensor and/or strain gauge to computationally correct for the effect of temperature or strain changes.

ULTRA-LOW NOISE, HIGHLY STABLE SINGLE-MODE OPERATION, HIGH POWER, BRAGG GRATING BASED SEMICONDUCTOR LASER

A laser including: a gain chip; an external cavity incorporating a Bragg grating; and a baseplate; wherein a first end of the gain chip has a high reflectivity facet forming a first end of the laser cavity; a second end of the gain chip has a low reflectivity facet; and a second part of the external cavity comprises a Bragg grating, supported by the baseplate, the temperature of the baseplate being maintained through a feedback loop; wherein the optical length of the external cavity is at least an order of magnitude greater than the optical length of the gain chip; wherein the Bragg grating is physically long and occupies a majority of the length of the external cavity and is apodized to control the sidemodes of the grating reflection. 1. A laser comprising:a semiconductor gain chip;an external cavity; anda first thermally conductive baseplate;wherein a first end of the gain chip has a high reflectivity facet forming a first end of the laser cavity; a second end of the gain chip has a low reflectivity facet, allowing light generated from the gain chip to be coupled with a first end of the external cavity;and a second part of the external cavity comprises a Bragg grating forming a second end of the laser cavity;wherein the external cavity comprising the Bragg grating is supported by the first thermally conductive baseplate;wherein the optical length of the external cavity is at least an order of magnitude greater than the optical length of the gain chip;wherein the physical length of the Bragg grating is greater than 20 mm and occupies at least 75% of the physical length of the external cavity; andwherein the Bragg grating is apodized to control the sidemodes of the grating reflection.2. The laser of claim 1 , wherein the external cavity comprises an optical fiber.3. The laser of claim 2 , wherein the Bragg grating is a fiber Bragg grating (FBG) within the optical fiber.4. The laser of claim 1 , wherein the external cavity comprises a waveguide.5. The laser of claim ...

LASER CONTROL

The description relates to laser control. One example can include a laser that has a laser emitter configured to generate a laser beam for intervals of time (e.g., pixel times). The laser can have a compensation and control component configured to receive a predicted laser emitter temperature of the laser emitter, obtain a desired optical power for an interval, and compute a compensated electrical current for the interval utilizing multiple light to current look up tables. Individual light to current look up tables can relate to specific laser emitter temperatures. 1. A system , comprising:a laser that comprises a laser emitter configured to generate a laser beam;a sensor configured to sense a temperature of a case of the laser;a laser emitter temperature prediction model that can model thermal impedance of the laser from the laser emitter to the case to predict laser emitter temperature from the sensed temperature of the case of the laser; and,a compensation and control component configured to receive a desired optical power and to compute a compensated electrical current to drive the laser based upon the predicted laser emitter temperature, the compensated electrical current computed for the predicted laser emitter temperature to cause the laser emitter to generate the laser beam having an actual optical power that matches the desired optical power.23-. (canceled)4. The system of claim 1 , wherein the thermal impedance reflects elements that have a thermal relationship with the laser emitter.5. The system of claim 4 , wherein the elements include another laser emitter.6. The system of claim 1 , wherein the laser emitter temperature prediction model can model thermal characteristics and internal temperature of the laser over time.7. The system of claim 6 , wherein the laser emitter temperature prediction model can model a particular point on the laser as a function of time and power.8. The system of claim 7 , wherein the laser emitter temperature prediction model ...

Laser assembly that provides an adjusted output beam having symmetrical beam parameters

A laser assembly ( 10 ) for providing a beam ( 20 ) includes a gain chip ( 12 ) and an axisymmetric optical assembly ( 16 ). The gain chip ( 12 ) emits an astigmatic, output beam ( 14 ). The optical assembly ( 16 ) adjusts the output beam ( 14 ) so that an adjusted output beam ( 20 ) has an adjusted first axis divergence angle and an adjusted second axis divergence angle. In certain embodiments, a magnitude of the adjusted first axis divergence angle is approximately equal to a magnitude of an adjusted second axis divergence angle in the far field.

OPTICAL TIME DOMAIN REFLECTOMETER USING POLYMER WAVELENGTH TUNABLE LASER

The present invention relates to an optical time domain reflectometer using, as a optical source, a polymer wavelength tunable laser which tunes the wavelength of an optical signal by using polymer grating. The optical time domain reflectometer of the present invention tunes the wavelength of a polymer wavelength tunable laser that outputs a constant optical signal and inspects cutting, reflection, and damage of an optical line by separating an optical signal returning from the optical line by an optical filter having a specific central wavelength. Since a optical source having a constant light intensity is used, the present invention has an effect of reducing the nonlinear effect generated in an optical line. 1. An optical time domain reflectometer , comprising:a wavelength-tunable laser configured to output an optical signal having a wavelength that varies with time in response to a control signal received from a controller; andan optical filter configured to selectively pass a reflected optical signal having a predetermined wavelength among a plurality of reflected optical signals that are returned from an optical fiber cable.2. The optical time domain reflectometer of claim 1 , whereinthe wavelength of the optical signal varies between a first wavelength and a second wavelength, andthe optical filter configured to pass a reflected optical signal having the second wavelength.3. The optical time domain reflectometer of claim 1 , wherein an intensity of the optical signal is maintained at a constant level.4. The optical time domain reflectometer of claim 1 , whereinthe control signal has at least two levels, andthe wavelength of the optical signal varies corresponding to each level of the control signal.5. The optical time domain reflectometer of claim 1 , wherein the wavelength-tunable laser comprises:a laser diode for generating the optical signal;an optical waveguide for changing the wavelength of the optical signal according to a temperature; anda thermal ...

Method for controlling tunable wavelength laser

In the method for controlling a tunable wavelength laser, information designating an oscillation wavelength is inputted. A driving condition for causing laser oscillation at a first wavelength is acquired from a memory. A control value of wavelength characteristics of the etalon and a difference between the first wavelength and a second wavelength are referred to, and a control value of wavelength characteristics of the etalon for causing laser oscillation at the second wavelength is calculated. The control value of wavelength characteristics of the etalon are assigned to the tunable wavelength laser, and a wavelength is controlled so that a wavelength sensing result becomes a first target value. Information indicating a wavelength shift amount from the designated oscillation wavelength is inputted. The wavelength sensing result is calculated as a second target value. The wavelength is controlled so that the wavelength sensing result becomes the second target value.

CONTINUOUS WAVE ULTRAVIOLET LASER BASED ON STIMULATED RAMAN SCATTERING

The present application is directed to a laser system using Stimulated Raman Scattering and harmonic conversion to produce a continuous wave ultraviolet wavelength output signal. More specifically, the laser system includes a pump source configured to generate at least one pump signal, a resonant cavity resonant at a Stokes wavelength in optical communication with the pump source, a SRS gain device positioned within the resonant cavity and configured to generate at least one SRS output signal at a Stokes wavelength when pumped with the pump signal, and a harmonic conversion device positioned within the resonant cavity and configured to produce a continuous wave second harmonic output signal of the SRS output signal. 1. A laser system , comprising:at least one pump source configured to generate at least one pump signal, the pump source having a wavelength of about 500 nm to about 550 nm;at least one resonant cavity in optical communication with the pump source, the resonant cavity resonant at a Stokes wavelength and defined by a first mirror and at least a second mirror;at least one SRS gain device positioned within the resonant cavity, the SRS gain device configured to generate at least one SRS output signal at a Stokes wavelength when pumped with the pump signal; andat least one harmonic conversion device positioned within the resonant cavity, the harmonic conversion device configured to produce a second harmonic output signal of the SRS output signal, wherein the second minor is configured to output the second harmonic output signal produced by the harmonic conversion device.2. The device of wherein the pump signal has a wavelength of about 532 nm.3. The device of wherein the pump laser comprises a diode pumped solid state laser.4. The device of further comprising at least one optical element configured to focus the pump signal into SRS gain device.5. The device of wherein the SRS gain device comprises diamond.6. The device of wherein the SRS output signal has a ...

OPTIMIZATION OF THE LASER OPERATING POINT IN A LASER ABSORPTION SPECTROMETER

An operating value of a first laser parameter of a laser device in a laser absorption spectrometer is optimized. The wavelength of laser device emitted light is adjusted by the first or a second laser parameter. The laser absorption spectrometer comprises a light intensity detector measuring the laser light intensity from the laser device. For each of multiple values of the first laser parameter: the light intensity detector measures light intensity obtained across a range of second laser parameter values, and an extremum in the light intensity measure and a peak position for the extremum are identified. A range of first laser parameter values is identified within the values of the first laser parameter for which there is a continuous trend in changes to the identified peak position with changes to the first laser parameter. The first laser parameter operating value is set to be within the identified range. 1. A method for optimizing an operating value of a first laser parameter of a laser device in a laser absorption spectrometer , wherein the wavelength of laser light emitted from the laser device is variable by adjusting either of the first laser parameter and a second laser parameter of the laser device , and wherein the laser absorption spectrometer includes a light intensity detector configured to measure the intensity of laser light received from the laser device , the method comprising: obtaining a measure of light intensity received at the light intensity detector across a range of values of the second laser parameter;', 'identifying an extremum in the measure of light intensity; and', 'identifying a peak position for the extremum;, 'for each of a plurality of values of the first laser parameteridentifying a range of values of the first laser parameter within the plurality of values of the first laser parameter for which there is a continuous trend in changes to the identified peak position with changes to the first laser parameter; andsetting the operating ...

Spectrometer Optical Head Assembly

An optical head assembly for use in a spectrometer is provided that is configured to characterize one or more constituents within a sample gas. The assembly includes a thermoelectric cooler (TEC) having a cold side on one end and a hot side on an opposite end, a cold plate in thermal communication with the cold side of the TEC, a hot block in thermal communication with the hot side of the TEC, a light source in thermal communication with the cold plate such that a change in temperature of the TEC causes one or more properties of the light source (e.g., wavelength, etc.) to change, and an optical element in thermal communication with the cold plate positioned to collimate light emitted by the light source through the sample gas (such that properties of the optical element vary based on a change in temperature of the TEC). 1. An optical head assembly for use in a spectrometer that is configured to characterize one or more constituents within a sample gas , the assembly comprising:a thermoelectric cooler (TEC) having a cold side on one end and a hot side on an opposite end;a cold plate in thermal communication with the cold side of the TEC;a hot block in thermal communication with the hot side of the TEC;a light source in thermal communication with the cold plate such that a change in temperature of the TEC causes one or more properties of the light source to change; andan optical element in thermal communication with the cold plate positioned to collimate light emitted by the light source through the sample gas, wherein properties of the optical element vary based on a change in temperature of the TEC.2. The assembly of claim 1 , wherein the optical element is coupled to the cold plate by a lens mount.3. The assembly of further comprising:a detector in thermal communication with the cold plate positioned to detect light emitted by the light source after passing through the optical element.4. The assembly of further comprising:a detector lens in thermal communication ...

Systems for Optical Power Control for Laser Safety of a Time-of-Flight Illumination System

A system is disclosed which includes a laser which has a calibrated optical power and a calibrated tolerance. The system includes a driving circuit configured to generate a first current pulse and a second current pulse. The system includes a primary observer module configured to observe a first and second primary input. The system includes one or more secondary observer modules configured to observe one or more first and one or more second secondary inputs. The system includes a controller communicatively coupled to the laser, driving circuit, primary observer module, and the one or more secondary observer modules. The controller is configured to receive an information packet, calculate an optical power, determine a deviation of the optical power from the calibrated optical power, compare the deviation with the calibrated tolerance, and perform an action if the deviation exceeds the calibrated tolerance. 1. A system comprising:a laser characterized by having a calibrated optical power and a calibrated tolerance, wherein each of the calibrated optical power and the calibrated tolerance is a constant; generate a first current pulse, and', 'generate a second current pulse after the first current pulse;, 'a driving circuit configured to observe one or more first primary inputs as generated by the laser in response to the first current pulse, and', 'observe one or more second primary inputs generated by the laser in response to the second current pulse;, 'a plurality of primary observer modules configured to observe one or more first secondary inputs generated by the laser in response to the first current pulse, and', 'observe one or more second secondary inputs generated by the laser in response to the second current pulse; and, 'a plurality of secondary observer modules configured to receive an information packet including the one or more first primary inputs, the one or more second primary inputs, the one or more first secondary inputs, and the one or more second ...

Radiation output device and method thereof

The present application provides a radiation output device and a method. The radiation output device includes a radiation generating module configured to generate initial radiation; a filter module configured to reflect a portion of a first preset wavelength of the initial radiation to the radiation generating module and transmit a portion of a second preset wavelength of the initial radiation, the transmitted radiation is therefore used as an output radiation of the radiation output device; a detection feedback module, using a portion of or all of the output radiation as a feedback radiation, configured to instruct a modulating module to modulate the filter module according to the feedback radiation. The modulating module is connected to the filter module and configured to modulate a position and/or an angle of the filter module according to the instruction of the detection feedback module.

LIGHT EMITTING DEVICE

A light emitting device includes a wiring substrate, a light emitting element array that includes a first side surface and a second side surface facing each other, and a third side surface and a fourth side surface connecting the first side surface and the second side surface to each other and facing each other, the light emitting element array being provided on the wiring substrate, a driving element that is provided on the wiring substrate on the first side surface side and drives the light emitting element array, a first circuit element and a second circuit element that are provided on the wiring substrate on the second side surface side to be arranged in a direction along the second side surface, and a wiring member that is provided on the third side surface side and the fourth side surface side and extends from a top electrode of the light emitting element array toward an outside of the light emitting element array. 1. A light emitting device comprising:a wiring substrate;a light emitting element array, provided on the wiring substrate;a driving element, provided on the wiring substrate; anda wiring pattern, provided on the wiring substrate;wherein the wiring pattern connects the light emitting element array to the driving element.2. The light emitting device according to claim 1 ,wherein the light emitting element array and the driving element are arranged linearly in a first direction, andthe wiring pattern is provided linearly in the first direction.3. The light emitting device according to claim 2 ,wherein the wiring substrate has a plane shape extending in the first direction and a second direction orthogonal to the first direction, andin a third direction orthogonal to the first direction and the second direction, an end side of the wiring pattern in the first direction is interposed between the driving element, and an other end side of the wiring substrate in the first direction is interposed between the light emitting array and the wiring substrate.4. ...

LIGHT SOURCE DRIVING APPARATUS AND IMAGE DISPLAY APPARATUS

A light source emits a laser light. A driver drives the light source based on a driving signal constituted by a pulse that changes a driving current value. When a luminance corresponding to a first laser output power that exceeds a threshold value is to be expressed, a controller controls the driver to supply to the light source a pulse having a first duty cycle at a first driving current value corresponding to the first laser output power. When a luminance corresponding to a second laser output power that is equal to or less than the threshold value is to be expressed, the controller controls the driver to supply to the light source a pulse having a second duty cycle that is smaller than the first duty cycle at a second driving current value corresponding to a third laser output power that exceeds the threshold value. 1. A light source driving apparatus comprising:a light source constituted by a semiconductor laser that emits a laser light;a driver configured to drive the light source based on a driving signal constituted by a pulse having a predetermined duty cycle that changes a driving current value; anda controller configured to control the driver, when a luminance corresponding to a first laser output power exceeding a threshold value, which is a predetermined laser output power, is to be expressed by the laser light that is output by the light source, is configured to control the driver to supply to the light source a driving signal constituted by a pulse having a first duty cycle at a first driving current value corresponding to the first laser output power such that the light source emits a laser light having the first laser output power,', 'when a luminance corresponding to a second laser output power that is equal to or less than the threshold value is to be expressed by the laser light that is output by the light source, is configured to control the driver to supply to the light source a driving signal constituted by a pulse having a second duty cycle ...

Efficient Wavelength Tunable Hybrid Laser

A tunable hybrid laser has a gain chip and a wavelength selection chip. The wavelength selection chip includes a wavelength selective loop reflector. The wavelength selective loop reflector is configured to receive the amplified lightwave from the gain chip. The wavelength selective loop reflector includes a single optical coupler and a micro-ring resonator (MMR). The single optical coupler splits the amplified lightwave and provides portions thereof to different branches of the MRR. The MRR permits selection of a desired wavelength and reflects the portions of the amplified lightwave at the desired wavelength back to the single optical coupler, which combines the portions of the amplified lightwave at the desired wavelength to generate a reflection lightwave and a transmission lightwave. The reflection lightwave is returned to the gain chip to form the external cavity and the transmission lightwave is output from the tunable hybrid laser. 1. A tunable hybrid laser , comprising:a gain chip configured to generate an amplified lightwave;a wavelength selection chip coupled to the gain chip, the wavelength selection chip comprising a wavelength selective loop reflector configured to receive the amplified lightwave from the gain chip, the wavelength selective loop reflector including a single optical coupler and at least one micro-ring resonator (MRR), the single optical coupler configured to split the amplified lightwave and provide portions of the amplified lightwave to different branches of the at least one MRR, the at least one MRR configured to permit selection of a desired wavelength and to reflect the portions of the amplified lightwave at the desired wavelength back to the single optical coupler, the single optical coupler configured to combine the portions of the amplified lightwave at the desired wavelength to generate a reflection lightwave and a transmission lightwave, the reflection lightwave returned to the gain chip to form the external cavity and the ...

Packaging structure and method of packaging tunable laser device, and tunable laser device

The present disclosure provides a packaging structure and a method of packaging an tunable laser device, and an tunable laser device. The packaging structure of the tunable laser device may include a TO tube base and a TO tube cap, wherein a first thermal sink is disposed on the TO tube base, a semiconductor laser chip is disposed on a vertical side of the first thermal sink, an aspheric lens is disposed on the TO tube cap, and the semiconductor laser chip is disposed on a central axis of the aspheric lens; and wherein the vertical side of the first thermal sink is a side of the first thermal sink perpendicular to the TO tube base. The tunable laser device according to the present disclosure may be applicable to communication over an optical fiber.

LIGHT EMISSION MODULE

A light emission module includes a base, a laser diode driver, a laser diode and a monitor photodiode. The laser diode driver, the laser diode and the monitor photodiode are disposed on the base. The monitor photodiode and the laser diode are located close to a front end of the laser diode driver. A rear side of the laser diode facing the front end of the laser diode driver. A end surface at the front end of the laser diode driver, a side surface at the rear side of the laser diode and a light receiving surface of the monitor photodiode are arranged in a triangle shape for reflecting a light emitted from the rear side of the laser diode to the light receiving surface of the monitor photodiode by the end surface of the laser diode driver. 1. A light emission module comprising a base , a laser diode driver , a laser diode and a monitor photodiode , the laser diode driver , the laser diode and the monitor photodiode disposed on the base , the monitor photodiode and the laser diode located close to a front end of the laser diode driver , a rear side of the laser diode facing the front end of the laser diode driver , the laser diode driver having an end surface located at the front end , the laser diode having a side surface located the rear side , and the monitor photodiode having a light receiving surface; the end surface of the laser diode driver , the side surface of the laser diode and the light receiving surface of the monitor photodiode arranged in a triangle shape for reflecting a light emitted from the rear side of the laser diode to the light receiving surface of the monitor photodiode by the end surface of the laser diode driver.2. The light emission module of claim 1 , wherein an angle between the end surface of the laser diode driver and an emission axis of the laser diode is from 20 degrees to 60 degrees.3. The light emission module of claim 2 , wherein the angle between the end surface of the laser diode driver and an emission axis of the laser diode is ...

Light source apparatus, light source driving method, and observation apparatus

A light source apparatus according to an embodiment of the present technology includes a white light source, a plurality of laser light sources, a detection unit, and a light source control unit. The white light source emits white light. The plurality of laser light sources emit a plurality of laser lights capable of adjusting a color temperature of the white light. The detection unit is capable of detecting a failure of each of the white light source and the plurality of laser light sources. The light source control unit controls an intensity ratio of the plurality of laser lights that are emitted from the plurality of laser light sources in a case where the failure of the white light source is detected.

Coherent Optical Distance Measurement Apparatus and Method

This disclosure presents a non-contact, frequency modulated continuous wave (FMCW) coherent optical distance measuring system and method for determining a measured distance over a wide distance range and simultaneously with fine range resolution. The approach and apparatus presented within eliminates the need for expensive, high frequency post-detection electronics to perform the necessary signal processing to accurately determine distance. 1. A distance measuring apparatus , comprising:{'sub': 1', '1', '1, 'a first laser diode with a first frequency chirp dFand first chirp rate (dF/Tp);'}{'sub': 2', '2', '2, 'a second laser diode with a second frequency chirp dFand second chirp rate (dF/Tp);'}a planar lightwave circuit including a pair of photodetectors, a combiner optomechanically connected to a cascaded pair of 3 dB directional couplers, a gradient index rod lens, and a partially reflectiveFaraday mirror optomechanically coupled to the gradient index rod lens, wherein the first laser diode is optically coupled to a first input port of the combiner, the second laser diode is optically coupled to a second input port of the combiner, a first output port of the combiner is optically coupled to a first input port of a first 3 dB directional coupler, a first output port of the first directional coupler is optomechanically coupled to the gradient index rod lens, the second input port of the first directional coupler is optomechanically connected to a first input port of a second directional coupler, and the two output ports of the second directional coupler are each optomechanically coupled to a photodetector;further comprising a third laser diode optomechanically coupled to a first input port of a second combiner on the planar lightwave circuit, and a fourth laser diode optomechanically coupled to a second input port of the second combiner, a third photodetector coupled to a first output port of the second combiner, and a fourth photodetector optomechanically coupled ...

Tunable Laser

Provided is a tunable laser that prevents basic characteristics of the laser from deteriorating and enables a high-speed control of the oscillation wavelength. The tunable laser includes a semiconductor gain portion including a III-V compound semiconductor, an optical feedback portion configured to diffract light generated in the semiconductor gain portion and feed the diffracted light back to the semiconductor gain portion, and an optical modulation portion including an optical waveguide that contains doped indirect transition-type silicon. The semiconductor gain portion and the optical modulation portion are disposed so that optical modes thereof overlap each other, and the semiconductor gain portion includes an embedded active layer thin film of a type in which a current is injected in a lateral direction. 1. A tunable laser comprising:a semiconductor gain portion including a III-V compound semiconductor;an optical feedback portion configured to diffract light generated in the semiconductor gain portion and feed the diffracted light back to the semiconductor gain portion; andan optical modulation portion including an optical waveguide that contains doped indirect transition-type silicon, whereinthe semiconductor gain portion and the optical modulation portion are disposed so that optical modes thereof overlap each other.2. The tunable laser according to claim 1 , whereinthe semiconductor gain portion includes an embedded active layer thin film of a type in which a current is injected in a lateral direction.3. The tunable laser according to claim 1 , whereinthe optical waveguide of the optical modulation portion includes a silicon optical modulator that includes a rib structure.4. The tunable laser according to claim 1 , whereinthe optical feedback portion includes a diffraction grating formed on the semiconductor gain portion.5. The tunable laser according to claim 4 , whereinthe diffraction grating includes a SiN film or a SiON film that contains deuterium.6. ...

MANAGING DATA FLOW IN VCSEL-BASED OPTICAL COMMUNICATIONS SYSTEM

Methods according to the disclosure include methods for managing data flow in an optical communications system having a plurality of vertical cavity surface emitting lasers (VCSELs). The method generally includes determining whether operation of the system exceeds a thermal threshold for a thermal parameter of the system, and switching from a first data bandwidth to a second data bandwidth when the thermal threshold is exceeded. Operation at the second data bandwidth further includes determining whether further operation of the system demands the first data bandwidth, and resuming operation of the system at the first data bandwidth only when the thermal parameter during operation at the second data bandwidth does not exceed the thermal threshold. 1. A method for managing data flow in an optical communications system having a plurality of vertical cavity surface emitting lasers (VCSELs) , the method comprising:determining, during operation of the optical communications system at a first data bandwidth, whether a thermal parameter of the optical communications system violates a thermal threshold; and determining whether the second data bandwidth meets a bandwidth demand on the optical communications system,', 'in response to the second data bandwidth meeting the bandwidth demand, continuing the operating of the optical communications system at the second data bandwidth, and', 'in response to the second data bandwidth not meeting the bandwidth demand, determining, during operation of the optical communications system at the second data bandwidth, whether the thermal parameter of the optical communications system violates the thermal threshold, and resuming the operating of the optical communications system at the first data bandwidth if the thermal parameter of the optical communications system does not violate the thermal threshold., 'in response to the thermal parameter of the optical communications system violating the thermal threshold, operating the optical ...

OPTICAL CHANNEL-TO-WAVELENGTH TUNING

An optical system includes an optical transmitter having optical transmission channels and an optical receiver having optical reception channels. The optical transmission channels are successively tuned to resonant wavelengths at which lowest transmission channel input currents result in transmission channel output current peaks greater than a threshold. The optical reception channels are tuned to the resonant wavelengths after the optical transmission channels are tuned. Each resonant wavelength has the optical reception channel tuned thereto that has a highest reception channel output current peak at a lowest reception channel input current when the optical transmission channel tuned to the resonant wavelength is temporarily detuned. 1. A method for tuning optical transmission channels of an optical transmitter to optical wavelengths , comprising: sweeping a resistive heater of the optical transmission channel through a range of input currents to vary an operative optical wavelength that an optical modulator of the optical transmission channel modulates in accordance with an input data bitstream;', 'as the resistive heater is swept through the range of input currents, monitoring an output current of a photodetector of the optical transmission channel that monitors the modulated operative optical wavelength; and', 'tuning the optical transmission channel to the optical wavelength corresponding to a lowest input current of the resistive heater at which a peak greater than a threshold was encountered within the monitored output current of the photodetector., 'for each optical transmission channel of the optical transmitter2. The method of claim 1 , wherein sweeping the resistive heater through the input currents claim 1 , monitoring the output current of the photodetector claim 1 , and tuning the optical transmission channel are successively performed for each optical transmission channel from a first optical transmission channel through a last optical transmission ...

WAVELENGTH-TUNABLE PLUGGABLE OPTICAL MODULE, OPTICAL COMMUNICATION SYSTEM AND WAVELENGTH CHANGE METHOD OF WAVELENGTH-TUNABLE PLUGGABLE OPTICAL MODULE

A pluggable electric connector can communicate a communication data signal and a control signal with an optical communication device. An optical signal output unit is configured to be capable of selectively output a wavelength of an optical signal. An optical power adjustment unit can adjust optical power of the optical signal. A pluggable optical receptor can output the optical signal to an optical fiber. A control unit controls a wavelength change operation according to the control signal. The control unit, according to a wavelength change command, commands the optical power adjustment unit to block output of the optical signal, commands the light signal output unit to change the wavelength of the optical signal after the optical signal is blocked, and commands the light signal output unit and the optical power adjustment unit to output the optical signal after the wavelength change operation. 113-. (canceled)14. A pluggable optical module comprising:an electrical connector configured to connect with a host communication apparatus;an optical connector configured to connect an optical fiber with an optical fiber connector;an optical light source configured to output a first wavelength light;a modulator configured to modulate the first wavelength light based on an electric signal received from the host communication apparatus via the electrical connector and output a first optical signal;an optical attenuator configured to control power of the first optical signal output to the optical fiber via the optical connector; anda controller configured to perform a wavelength change operationin response to a wavelength change command from the host communication apparatus via the electrical connector, the optical attenuator blocks the first optical signal;', 'the optical light source changes the first wavelength light to a second wavelength light after the optical attenuator blocks the first optical signal; and', 'the optical attenuator outputs a second optical signal after ...