СОХРАНЯЮЩЕЕ СОСТОЯНИЕ ПОЛЯРИЗАЦИИ ОПТИЧЕСКОЕ ВОЛОКНО МАЛОГО ДИАМЕТРА

Изобретение относится к области оптических волокон. Сохраняющее состояние поляризации оптическое волокно малого диаметра включает кварцевое оптическое волокно, вокруг внешней оболочки которого расположен слой внутреннего покрытия и слой внешнего покрытия, а во внутренней оболочке кварцевого оптического волокна находится сердцевина и кварцевая оболочка, между которыми находятся зоны напряжения; между слоями внутреннего и внешнего покрытия находится слой буферного покрытия. По периферии каждой зоны напряжения находится коаксиально расположенный защитный буферный слой. Когда рабочая длина волны оптического волокна с сохранением поляризации малого диаметра составляет 1310 нм, затухание снижается до менее 0,5 дБ/км, а переходное затухание достигает -35 дБ/км; при рабочей длине волны, равной 1550 нм, затухание снижается до менее 0,4 дБ/км, а переходное затухание достигает -30 дБ/км. Технический результат - устойчивость к затуханию и стабильность работы в течение долгого времени, повышение точности ...

MACH ZEHNDER INTERFEROMETER

Optical delay line arrangement

An optical delay line arrangement, for use for example as part of a means for generating false radar returns, comprises a plurality of main optical transmission lines 1, each main line including at least one delay element 2 having a plurality of delay lines having different delay times and means for coupling a respective one of the delay lines into its respective main line; means 6 for tapping off a proportion of an optical signal travelling along the main line on either side of the delay element; and a switch 20 comprising a waveguide having an input and an output for each of the main lines and an electrode arrangement 24 operative to cause a light signal to be directed to one of the outputs by means of the electro-optic effect. Optical signals tapped at each storage are combined at 7 and detected at 10. The resulting electrical signals are amplitude 12 and phase 13 adjusted, combined 14 and emitted 15, the signals from each main line resembling the signature of a ship.

Method of manufacturing knitted briefs

A plurality of brief blanks are knitted interconnected in side-by-side relationship upon a circular knitting machine. The tube is then slit, either on or off the knitting machine, to sever the interconnection, the slit portions being then coursewise separated to provide a plurality of brief blanks of the required form.

METHOD OF MANUFACTURING KNITTED BRIEFS

Communication apparatus

FIBRE MODULATORS

OPTICAL POLARISATION STATE CONTROLLERS

Tunable nonlinearly chirped grating.

A nonlinearly chirped fiber grating (100)for achieving tunable dispersion compensation, chirp reduction in directly modulated diode lasers (102), and optical pulse manipulation. A dynamical dispersion compensation mechanism can be implemented in a fiber communication system based on such a nonlinearly chirped fiber grating (100).

Tunable nonlinearly chirped grating

Tunable nonlinearly chirped grating.

IMPROVEMENTS ON ACCELEROMETERS

SINGLE-SIDEBAND MODULATOR WITH AN OPTICAL MONOMODE FIBER.

WAVELENGTHSELECTIVE OPTICAL WELLENLEITERKUPPLER.

FIBER-OPTIC DEVICE FOR FREQUENZVERSCHIEBUNG.

Acousto-optic variable attenuator with active cancellation of back reflections

Fiber optic sensor system and method

ACOUSTO-OPTIC FREQUENCY SHIFTER UTILISING MULTI-TURN OPTICAL

INTERFEROMETER WITH A TUNABLE OPTICAL RESONATOR INCORPORATING A MONOMODE OPTICAL FIBRE AND APPLICATION TO FILTERING AND SPECTOGRAPHY

FIBER OPTIC MODAL COUPLER

FORM BIREFRINGENT CUTOFF POLARIZER

METHOD FOR CONTROLLING THE POLARISATION OF AN OPTICAL SIGNAL AND AN OPTICAL COMPONENT FOR POLARISATION CONTROL OF LIGHT IN PLANAR WAVEGUIDES

By a method for controlling the state of polarisation (SOP) of an optical signal transmitted through an optical waveguide, the waveguide is buried in a planar structure and a plurality of stress-applying films, having variable stress, are placed on the top of the structure. Preferably the stress-applying films comprise materials that have thermal expansion coefficients different from that of the planar structure or comprise materials with piezo-electric properties. In this way it is possible to produce a cascaded series of optical elements with variable linear birefringence in a planar optical waveguide. Moreover according to the invention it is possible, by the method according to the invention, to manufacture optical components having an active polarisation controller.

DEVICE FOR TUNING A BRAGG GRATING BY MEANS OF COMPRESSION USING A PIEZOELECTRIC ACTUATOR

Dipositif d'accord d'un réseau de Bragg, par compression au moyen d'un actionneur piézoélectrique. Ce dispositif s'applique notamment aux télécommunications optiques et comprend par exemple des moyens (8) de compression d'une portion (4) de fibre optique, contenant un réseau de Bragg (2), et des moyens (10) pour empêcher le flambage de cette portion, un tube (14) traversé par la portion et des moyens (32, 10 34) de guidage de cette portion dans le tube. Les moyens de compression comprennent un élément déformable incurvé (8) et un actionneur piézoélectrique (20, 22) qui est disposé entre l'élément et le tube, s'allonge lorsqu'il est excité et déforme alors l'élément, ce dernier comprimant alors la portion.

PHASE MODULATOR, PHASE MODULATOR ASSEMBLY, AND PHOTOSENSOR

The present invention provides a photosensor that uses a phase modulation technique for optical detection and conducts a highly accurate measurement. The photosensor uses a phase change difference of light propagated through a polarization preserving fiber with respect to tensile stress and employs proper polarization preserving fibers for a phase modulator 10, light-transmitting polarization preserving fiber 23, and coil-shaped polarization preserving fiber 30, to achieve a highly accurate measurement.

Integrated Optical Devices Utilizing Magnetostrictively, Electrostrictively or Photostrictively Induced Stress

Integrated optical devices which utilize a magnetostrictively, electrostrictively or photostrictively induced stress to alter the optical properties of one or more waveguides in the device are disclosed. The integrated optical devices consist of at least one pair of optical waveguides preferably fabricated in a cladding material formed on a substrate. A stress applying material, which may be a magnetostrictive, electrostrictive or photostrictive material, is affixed to the upper surface of the cladding material near at least one of the optical waveguides. When the appropriate magnetic, electric or photonic field is applied to the stress applying material, a dimensional change tends to be induced in the stress applying material. The constrained state of the stress applying material, however, caused by its adhesion to the cladding material, causes regions of tensile and compressive stress, as well as any associated strains, to be created in the integrated optical device. By positioning one or more optical waveguides in a region of the device which will be subjected to a tensile or compressive stress, the optical properties of the stressed waveguide may be varied to achieve switching and modulation. Latchable integrated optical devices are achieved by utilizing a controlled induced stress to "tune" one or more waveguides in an integrated optical device to a desired refractive index or birefringence, which will be retained after the field is removed.

ОСУЩЕСТВЛЕНИЕ НЕЛИНЕЙНОЙ НАСТРОЙКИ ОПТИЧЕСКОЙ ДИСПЕРСИИ С ИСПОЛЬЗОВАНИЕМ БРЭГГОВСКОЙ ВОЛОКОННОЙ РЕШЕТКИ

... 1. Оптическое устройство, включающее волноводный элемент, имеющий оптическую ось, предназначенный для передачи оптической энергии и имеющий эффективный показатель преломления вдоль оптической оси; и область оптического возмущения, образованную в волноводном элементе и сконфигурированную с периодом вдоль оптической оси, при этом значение периода и эффективного показателя преломления является нелинейной функцией в зависимости от положения вдоль оптической оси для удовлетворения условию фазового согласования, так что отраженная оптическая волна от области оптического возмущения имеет длину волны, которая нелинейно зависит от положения вдоль оптической оси. 2. Устройство по п.1, отличающееся тем, что указанный период изменяется нелинейно вдоль оптической оси. 3. Устройство по п.1, отличающееся тем, что волноводный элемент включает оптическое волокно. 4. Устройство по п.1, отличающееся тем, что волноводный элемент включает оптический волновод. 5. Устройство по п.1, отличающееся тем, что дополнительно ...

TRANSMISSIVE OPTICAL FILTER

ATTENUATOR HAS FIBEROPTICS

L'INVENTION CONCERNE LES COMPOSANTS OPTIQUES. UN ATTENUATEUR A FIBRES OPTIQUES 10 EST FORME PAR LA COMBINAISON EN CASCADE D'UNE FIBRE BIREFRINGENTE PRESERVANT LA POLARISATION 12 ET D'UNE FIBRE A POLARISATION UNIQUE 14. EN FAISANT VARIER DE FACON CONTINUE LA BIREFRINGENCE LOCALE DE LA FIBRE BIREFRINGENTE, PAR EXEMPLE SOUS L'EFFET D'UN EFFORT DE TRACTION, DE LA PRESSION OU DE LA TEMPERATURE, ON MODIFIE LA DIFFERENCE DE PHASE ENTRE LES DEUX COMPOSANTES DE POLARISATION DE LA LUMIERE TRAVERSANT LA FIBRE BIREFRINGENTE. CECI PROVOQUE LA SUPPRESSION DE L'UNE DE SES COMPOSANTES AU PASSAGE DANS LA FIBRE A POLARISATION UNIQUE, CE QUI ATTENUE LE SIGNAL DE SORTIE DE CETTE FIBRE, QUI EST LA SOMME DE DEUX POLARISATIONS. APPLICATION AUX TELECOMMUNICATIONS OPTIQUES. THE INVENTION CONCERNS OPTICAL COMPONENTS. A FIBER OPTIC ATTENUATOR 10 IS SHAPED BY THE CASCADE COMBINATION OF A BIREFRINGENT FIBER PRESERVING POLARIZATION 12 AND A SINGLE POLARIZATION FIBER 14. BY VARIING THE LOCAL BIREFRINGENCE OF THE BIREFRINGENT FIBER CONTINUOUSLY, FOR EXAMPLE UNDER L. 'THE EFFECT OF A TENSILE EFFORT, PRESSURE OR TEMPERATURE, THE PHASE DIFFERENCE BETWEEN THE TWO POLARIZATION COMPONENTS OF LIGHT THROUGH THE BIREFRINGENT FIBER IS MODIFIED. THIS CAUSES THE DELETION OF ONE OF ITS COMPONENTS WHEN PASSING THROUGH THE SINGLE POLARIZATION FIBER, WHICH ATTENDS THE OUTPUT SIGNAL OF THIS FIBER, WHICH IS THE SUM OF TWO POLARIZATIONS. APPLICATION TO OPTICAL TELECOMMUNICATIONS.

OPTICAL SWITCHES AND LOGIC GATES EMPLOYING SAME

An optical switch including a light passageway having a changeable cross-sectional area, an activation light responsive piezoelectric element associated with the light passageway, the activation light responsive piezoelectric element being operative to change its shape in response to activation light impinging thereon and a conductive element operatively associated with the piezoelectric element for enhancing activation light responsiveness thereof, the activation light responsive piezoelectric element being associated with the light passageway and being operative such that changes in the shape of the piezoelectric element cause changes in the changeable cross-sectional area of the light passageway sufficient to govern the passage of light along the light passageway. Logic gates and logic functionality employing an optical switch are also described.

ALL FIBER POLARIZATION MODE DISPERSION COMPENSATOR

A polarization mode dispersion compensator corrects polarization mode dispersion in an optical signal having a fast polarization mode component, a slow polarization mode component and a time differential between the components. The compensator includes a phase shifter and a variable delay section. An input of the phase shifter is coupled to an optical device that provides an optical signal that exhibits polarization mode dispersion. The phase shifter functions to rotate the optical signal principal states of polarization to a desired orientation. The phase shifter engages a segment of an optical fiber that is coated with a radiation cured coatings. The coating composition is selected so that in response to a preload comprising the application of a stress of about 80 MPa to said coating at about 80 °C and after a stress-relaxation period of at least about 1 hour, at about 80 °C, a residual stress exhibited by said coating comprises at least about 60 MPa, and the coating is capable of transmitting ...

DYNAMICALLY RECONFIGURABLE COMPOSITE GRATING FILTERS FOR TEMPORAL WAVEFORM PROCESSING

L'invention concerne des codeurs (601) de guide d'ondes programmables, comprenant un ou plusieurs segments ondulés (609), et un ou plusieurs segments intermédiaires (613), formés sur ou dans un guide d'ondes défini par une âme (605), ces segments intermédiaires (613) étant commandés indépendamment par des tensions appliquées à chacune des électrodes de segment (617, 618). Les segments intermédiaires (613) permettent d'appliquer une modulation de phase à une entrée tandis que les segments ondulés agissent comme des réseaux, un signal de réseau central étant accordable par application d'une tension à une électrode associée au segment ondulé (609). Selon certains modes de réalisation, les codeurs comprennent uniquement des segments ondulés (609) ou uniquement des segments intermédiaires (613). Ces codeurs peuvent être accordés par contrainte ou thermiquement. Lesdits codeurs peuvent être accordés par programmation de façon à coder ou décoder un code de signal temporel ou un autre code.

GUIDED WAVE ELECTROOPTIC/ACOUSTOOPTIC TUNABLE FILTER

A two-port guided wave tunable filter in a birefringent electrooptic and/or acoustooptic substrate material includes two 3-port, symmetric Y-branch beamsplitters connected by two waveguide sections in which phase-matched polarization coupling occurs, with an input port and an output port. The optical path difference between the beamsplitters is half an optical wavelength, and the polarization coupling regions between the beamsplitters are relatively displaced by an odd integral multiple of half the spatial period of the pertubation responsible for the coupling. In an electrooptic tunable filter embodiment, the polarization coupling in the waveguides is caused by a spatially periodic strain-inducing film and tuning results from an applied electric field. In an acoustooptic tunable filter embodiment, polarization coupling results from a surface acoustic wave and tuning is accomplished by changing the acoustic frequency. Alternatively, four port electrooptic and acoustooptic tunable filters ...

Telecommunication systems

A telecommunication system has a laser-energized multimode optical fibre highway. Data is entered on to the highway by means of a series of modulators each operating at a different subcarrier frequency. At the far end of the highway demodulation is carried out be a quadrant photodetector which applies each of its outputs to a respective set of channels. Each channel in a set has a band pass filter centered on a subcarrier frequency followed by a non-linear device. The signals from all the channels of different sets carrying the same subcarrier frequency are combined and the signals passed through band pass filters centered on the second harmonic of the subcarrier frequency.

Optical polarisation state controllers

A planar coil of single mode fiber has opposed ends twisted into orthogonal planes to form a non-planar coil 20 exhibiting circular birefringence. The amount of birefringence exhibited is modulated by means of an electromechanical transducer 34 which controls the distance separating two diametrically opposed portions of the coil. Two or more such controllers may be formed in tandem with intervening additional coils 50 providing quarter-wave linear birefringence.

Optical device

An optical device comprises an optical fiber directional coupler having at least a first optical fiber optionally coupled at a coupling region to a second optical fiber such that light can propagate in the coupling region in at least two possible electromagnetic transmission modes; and means for transferring energy between the modes by a spatially periodic perturbation of at least a part of coupling region.

Optical path length modulator

An optical integrated circuit comprises an optical substrate and an optical waveguide supported by the substrate. A transducer is incorporated into the optical integrated circuit and coupled to the optical substrate. The transducer comprises a region of piezo-electric material and a set of electrodes for applying a voltage to the piezo-electric material for selectively causing the deformation of the piezo-electric material so as to alter the optical path length of the waveguide.

Acousto-optic filter

An acousto-optic filter has a non-birefringent single mode optical fiber with a longitudinal axis, a core and a cladding in a surrounding relationship to the core. The optical fiber has multiple cladding modes and a single core mode that is guided along the core. An acoustic wave propagation member has a proximal end and a distal end coupled to the optical fiber. The acoustic wave propagation member propagates an acoustic wave from the proximal to the distal end and launches a flexural wave in the optical fiber. At least one acoustic wave generator is coupled to the proximal end of the acoustic wave propagation member.

Add/drop acousto-optic filter

A drop AOTF has a first AOTF that includes an optical fiber with a longitudinal axis, an acoustic wave propagation member with a proximal end and a distal end and an acoustic wave propagation member. The acoustic wave propagation member propagating an acoustic wave from the proximal to the distal end of the acoustic wave propagation member. An optical circulator, with first, second and third ports, is coupled to the first AOTF at the third port. A mode coupler is coupled to the first AOTF. A orthogonal-polarization reflective mirror is coupled to the mode coupler.

Focused acoustic wave fiber optic reflection modulator

An improved optical fiber modulator producing a focused acoustic wave propagating from an acoustic transducer surrounding an optical fiber having an in-fiber reflection grating changes the core refractive index in proportion to the induced strain at the core when the focused acoustic wave arrives at the optical fiber core, and focused acoustic waves can also modulate optical carrier phase in a length of optical fiber which may lie in an arm of an interferometer. In a preferred embodiment, the index change shifts the reflection spectrum of an in-fiber grating located in the portion of optical fiber core on which the focused acoustic wave is centered with the reflection spectrum shift producing a change in the grating reflectivity for a narrow bandwidth optical signal on a skirt of the grating spectrum. Electronic multiplexing means may be used to both transmit and receive signal information on a single optical carrier signal, and a plurality of acoustic wave modulators may be placed along ...

Integrated optical devices utilizing magnetostrictively, electrostrictively or photostrictively induced stress

Integrated optical devices which utilize a magnetostrictively, electrostrictively or photostrictively induced stress to alter the optical properties of one or more waveguides in the device are disclosed. The integrated optical devices consist of at least one pair of optical waveguides preferably fabricated in a cladding material formed on a substrate. A stress applying material, which may be a magnetostrictive, electrostrictive or photostrictive material, is affixed to the upper surface of the cladding material near at least one of the optical waveguides. When the appropriate magnetic, electric or photonic field is applied to the stress applying material, a dimensional change tends to be induced in the stress applying material. The constrained state of the stress applying material, however, caused by its adhesion to the cladding material, causes regions of tensile and compressive stress, as well as any associated strains, to be created in the integrated optical device. By positioning one or more optical waveguides in a region of the device which will be subjected to a tensile or compressive stress, the optical properties of the stressed waveguide may be varied to achieve switching and modulation. Latchable integrated optical devices are achieved by utilizing a controlled induced stress to "tune" one or more waveguides in an integrated optical device to a desired refractive index or birefringence, which will be retained after the field is removed.

SINGLE MODE PROPAGATION IN FIBERS AND RODS WITH LARGE LEAKAGE CHANNELS

Various embodiments include large cores fibers that can propagate few modes or a single mode while introducing loss to higher order modes. Some of these fibers are holey fibers that comprise cladding features such as air-holes. Additional embodiments described herein include holey rods. The rods and fibers may be used in many optical systems including optical amplification systems, lasers, short pulse generators, Q-switched lasers, etc. and may be used for example for micromachining. 1. (canceled)2. An optical fiber for propagating at least one lower order mode having a wavelength λ , while limiting propagation of higher order modes having a wavelength λ by providing said higher order modes with a higher loss than said at least one lower order mode at said wavelength λ , said optical fiber comprising:a first cladding region comprising a plurality of holes having a diameter, d, and a center-to-center spacing, Λ, wherein the ratio d/Λ is larger than 0.4 and less than 0.95; anda core region surrounded by said first cladding region, said plurality of holes of the first cladding region providing confinement of said at least one lower order mode to the core region,wherein said core region has a width of at least 20 micrometers,wherein the ratio Λ/λ, is greater than 15 and less than 500, andwherein said optical fiber is configured such that said at least one lower order mode has no more than 1.0 dB/m of loss at a bending radius of 30 centimeters.3. The optical fiber of claim 2 , wherein said core and cladding regions are in a optically transmissive main body of said optical fiber claim 2 , said main body comprising material optically transmissive of said wavelength λ claim 2 , said main body having a width and thickness of at least 250 μm so as to reduce mode coupling of said lower order modes to said higher order modes.4. The optical fiber of claim 3 , said main body having a width and thickness of at least 500 μm5. The optical fiber of claim 2 , wherein said core region ...

SYSTEM FOR TRANSDUCTION OF DISPLACEMENT TO OPTICAL PHASE SHIFT

An optomechanical system including a guide structure, to guide a light beam; and two waveguide segments. Each guide structure include beams that together form two combs partially nested one in the other. At least one beam is free to move in translation along an axis orthogonal to the long axis of the guide structure. A displacement into an optical phase shift, while limiting additional effects on the intensity.

Thermally-controlled fiber optic tuning and isolating device

A tunable fiber optic component providing environmental isolation, thermal tuning, and mechanical tuning and a method of tuning a fiber optic component using application of substantially simultaneous varying of temperature and mechanical strain is disclosed. A method of using a tunable fiber optic component, for example, a distributed feedback fiber laser, to compensate variations in an optical system, and a method of making a tunable fiber optic component are also disclosed.

SECURITY SWITCH

The present disclosure relates to optical switching devices and switch modules that are designed for long-term security monitoring of high-value infrastructure access entry points. Embodiments in accordance with the present disclosure include optical switches based on fiber-Bragg gratings whose operating wavelengths are based on the presence or absence of magnetic coupling between an embedded permanent magnet and an external element. By monitoring the spectral position of the operating wavelengths and/or the magnitude of a light signal at the operating wavelengths, the state of the magnetic coupling can be determined and used as an indicator of whether the security switch has been actuated. 1. A switch module comprising:a first fiber-Bragg grating (FBG) portion that includes a first FBG characterized by a first operating wavelength, wherein the first FBG portion has a first length, and wherein the first operating wavelength is based on the first length; anda first magnet that is mechanically coupled with the first FBG portion such that a first motion of the first magnet induces a first change in the first operating wavelength.2. The switch module of further comprising:a housing that contains the first FBG portion and the first magnet; anda ferromagnetic element that is external to the housing;wherein the ferromagnetic element and the first magnet are configured such that (1) the magnetic coupling between them is based on a first separation between the housing and the ferromagnetic element and (2) a change in the first separation induces the first motion.3. The switch module of further comprising:a second FBG portion that includes a second FBG characterized by a second operating wavelength, wherein the second FBG portion has a second length, and wherein the second operating wavelength is based on the second length;a pivot assembly that includes a first attachment point and a second attachment point, wherein the pivot assembly is mechanically coupled with the first ...

Lamina for the rotation of the direction of polarisation in an optical fibre and its application

A wavelength selective optical waveguide coupler

A wavelength selective optical waveguide coupler (1) comprises a first undulatory optical D-fibre (2) and a second optical D-fibre (6) embedded in respective substrates (4,8). The fibres (2,6) are located adjacent one another, the undulations of the fibre (2) defining a set of regularly spaced optical coupling regions. This provides a readily formed coupler able to be accurately set to selectively couple a pre-selected wavelength by relatively coarse macroscopic adjustment.

INTERFEROMETER MIT OPTISCHEN FASERN UND PIEZOELEKTRISCHER MODULATOR MIT OPTISCHEN FASERN

Akusto-optische Modulationsvorrichtung mit einem optischen Wellenleiter

FASERMODULATOREN.

SCHALTUNGSANORDNUNG ZUR ERZEUGUNG EINER PHASENMODULATION IN EINER LICHTLEITFASER.

At least one part of the optical fibre is wound around or otherwise attached to a piezoelectric body (1) which is stimulated by a modulation voltage to produce the phase modulation. A phase modulation stabilisation stage is included. A measurement transducer (4,5) attached to the piezoelectric body (1) determines the oscillation state. A differential amplifier (8) compares the transducer output with a reference value in amplitude. A control element (7) influences the stimulation voltage amplitude according to the amplifier output. Alternatively, the modulation voltage can be compared with the transducer output in phase and the modulation voltage frequency regulated accordingly.

KOPPLUNGSELEMENT FUER MONOMODEFASER UND DIESES AUFWEISENDE UEBERTRAGUNGSSYSTEM.

Spannungsoptisches Phasenschieberarray für Lidar und andere Anwendungen

Ein optisches Element zum Übertragen eines Lichtstrahls beinhaltet einen Wellenleiter, der dazu konfiguriert ist, den Lichtstrahl von einem Eingangsende zu einem Ausgangsende zu übertragen, und der eine optische Eigenschaft aufweist, die durch Verformung des Wellenleiters modifiziert werden kann. Ein Phasenschieber ist an dem Wellenleiter angebracht und ist dazu funktionsfähig, als Reaktion auf ein Steuersignal den Wellenleiter ausreichend mechanisch zu verformen, um eine Phasenverschiebung in dem durch diesen hindurch übertragenen Lichtstrahl einzuführen. Der Phasenschieber kann eine PZT-Schicht beinhalten.

Einseitenband-Modulator mit einer optischen Monomode-Faser.

Improvements in and relating to accelerometers

Optical state-of-polarisation modulator

An optical measurement system includes a polarisation modulator having an element which is controlled to sweep the output polarisation state such that the time integral of the system photodetector output becomes independent of polarisation. It is shown that, on the Poincaré sphere, the output polarisation states must have a time-weighted distribution symmetrical about the sphere centre; in particular, the output state must sweep around a great circle at a uniform rate. The modulator may require to be preceded by an adjuster to bring the input polarisation state on to a given great circle. Embodiments with optical fibre 15 may use stress-induced linear birefringence 30, coupled if necessary with physical rotation (Figs. 5,6) or rotating stress (Fig. 7); magnetically-induced circular birefringence (Faraday effect) may alternatively be used (Fig. 8). The drive waveforms are triangular. The adjuster comprises two quarter-wave linearly-birefringent loops 29 of adjustable position. The system ...

OPTICAL FIBRE ATTENUATOR

MODULATOR

Optical delay lines

A method of applying a Doppler shift to an optical signal as it passes through an optical delay line comprises the step of progressively altering a property of the optical delay line during passage of the optical signal therethrough such that the time taken for the optical signal to pass therethrough is progressively lengthened or progressively shortened for successive portions of the optical signal. The optical delay line may comprise a stretchable optical fibre wound around a piezoelectric transducer 20 to which a sawtooth signal is applied to stretch and relax the fibre.

OPTICAL PHASE MODULATOR

Fibre optic sensor

A sensor assembly (1) comprises an optical fibre (4) and a transducer (23) arranged to apply transverse strain to a localised portion (24) of the fibre. Birefringence effects induced by the fibre strain are remotely sensed to obtain a signal representative of the transducer input which in turn is connected to a current sensing coil (34) thereby enabling electric current in a conductor (32) to be remotely sensed. The localised portion (24) of the fibre (4) is stripped to remove an outer jacket and is embedded in a relatively rigid matrix material. Damage to the fibre and the effects of creep are thereby avoided. The resulting sensor (36) is particularly suited to the measurement of high currents in power distribution systems.

Optical transmission filter

In manufacturing optical transmission filters having double-refraction elements, extreme care is usually necessary to provide the desired phase delay. To simplify the manufacturing process while still achieving accurate phase delay, a filter is provided with at least one double-refraction element comprising a single-mode optical filter mounted between polarizers. The double refraction of the optical fiber is sufficiently weak so that the lambda length within which light beams propagating with orthogonal polarization states in the fiber are mutually delayed by 2 pi , is at least 1 cm. In one embodiment, the optical fiber comprises alternating sections which produce linear double refraction with sections which produce elliptical double refraction.

OPTICAL STATE OF POLARISATION MODULATION

IMPROVEMENTS RELATING TO OPTICAL SENSORS

OPTICAL FIBER WITH SEVERAL TURNS AS ACUSTOOPTICAL FREQUENCY SLIDEGATE VALVES.

ACUSTOOPTICAL FREQUENCY SLIDEGATE VALVES.

PROCEDURE FOR THE PRODUCTION OF KNITTED SLIP TROUSERS.

FIBER-OPTIC FASHION COUPLER.

Methods of altering the resonance of waveguide micro-resonators

Optical device

FIBRE OPTIC PHASE MODULATOR

OPTICAL FIBRE SENSORS

FIBRE MODULATORS

DYNAMICALLY RECONFIGURABLE COMPOSITE GRATING FILTERS FOR TEMPORAL WAVEFORM PROCESSING

Programmable waveguide coders (601) are disclosed that include one or more corrugation segments (609) and one or more spacer segments (613) formed on or in a waveguide defined by a core (605) and the spacer segments (613) are independently controllable with voltages applied to each segment's electrodes (617, 618). The spacer segment s (613) permit application of a phase modulation to an input while the corrugation segments act as tunable gratings, wherein a cent er grating wavelength is tunable by applying a voltage to an electrode associated with the corrugation segment (609). In some embodiments , coders include only corrugation segments (609) or only spacer segments (613). Such coders can be strain tuned or thermally tuned. T he coders can be programmatically tuned to code or decode a time-wavelength code or other code.

TENSION ADJUSTED INLINE OPTICAL FIBER ATTENUATOR

An single-mode fiber attenuator is disclosed which may be formed by a tandem combination of a birefringent polarization-preserving fiber and a single polarization fiber. The birefringent fiber functions as a variable wave plate and the single polarization fiber functions as a fiber polarizer. By continuously changing the local birefringence of the birefringent fiber with, For example, tension, pressure, or temperature, the phase difference between the two polarization components of light traveling through the birefringent fiber is continuously modified. The difference in phase causes suppression of one of the polarization components as it enters the fiber polarizer and, therefore, the output of the fiber polarizer, the sum of the two polarizations, is attenuated. The attenuator may be tuned by changing the local birefringence of the birefringent fiber. An inline optical fiber bandpass filter may be formed by cascading a plurality of appropriately arranged inline fiber attenuators formed ...

COUPLING DEVICE FOR SINGLE MODE OPTICAL FIBER AND COMMUNICATIONS SYSTEM COMPRISING SAME

GUIDED WAVE ELECTROOPTIC/ACOUSTOOPTIC TUNABLE FILTER

A two-port guided wave tunable filter in a birefringent electrooptic and/or acoustooptic substrate material includes two 3-port, symmetric Y-branch beamsplitters connected by two waveguide sections in which phase-matched polarization coupling occurs, with an input port and an output port. The optical path difference between the beamsplitters is half an optical wavelength, and the polarization coupling regions between the beamsplitters are relatively displaced by an odd integral multiple of half the spatial period of the pertubation responsible for the coupling. In an electrooptic tunable filter embodiment, the polarization coupling in the waveguides is caused by a spatially periodic strain-inducing film and tuning results from an applied electric field. In an acoustooptic tunable filter embodiment, polarization coupling results from a surface acoustic wave and tuning is accomplished by changing the acoustic frequency. Alternatively, four port electrooptic and acoustooptic tunable filters ...

Optical External Modulator for Optical Telecommunications

FIBRE MODULATORS

... 2064562 9102276 PCTABS00003 A modulation assembly comprises a fibre (1) having a drawn tapered portion (2), and means (4, 5, 6, 7) for applying a perturbation to the tapered portion to vary the percentage transmission through the fibre.

METHOD AND SYSTEM WITH THE USE OF FIBER - OPTICAL SENSORS

CUSTOMIZABLE DIFFRACTION GRATING WITH NONLINEAR CHANGING PERIOD

Optical mode filter employing radially asymmetric fiber

DISPOSITIF MODULATEUR ELECTRO-OPTIQUE COMPORTANT UNE FIBRE OPTIQUE

LE DISPOSITIF DE L'INVENTION EST UN DISPOSITIF MODULATEUR ELECTRO-OPTIQUE COMPRENANT UNE FIBRE OPTIQUE 4 QUI COMPORTE UNE GAINE OPTIQUE EN MATERIAU PIEZOELECTRIQUE, DEUX ELECTRODES EXTERIEURES 11, 12 ETANT DISPOSEES SUR LA SURFACE EXTERIEURE DE CETTE GAINE, ET UNE ELECTRODE INTERIEURE 10 ENTRE CETTE GAINE 4 ET LE COEUR 15 DE LA FIBRE. UNE DIFFERENCE DE POTENTIEL V EST APPLIQUEE ENTRE LES DEUX ELECTRODES EXTERIEURES. L'INVENTION S'APPLIQUE NOTAMMENT A LA REALISATION DE MODULATEURS ELECTRO-OPTIQUES A COMMANDE ELECTRIQUE.

Filtre optique de transmission.

FILTRE OPTIQUE DE TRANSMISSION COMPORTANT AU MOINS UN CORPS BIREFRINGENT QUI EST CONSTITUE PAR UNE FIBRE OPTIQUE MONOMODE 41 DONT LA BIREFRINGENCE EST CHOISIE SUFFISAMMENT FAIBLE POUR QUE LA LONGUEUR L A L'INTERIEUR DE LAQUELLE LES FLUX LUMINEUX SE PROPAGEANT DANS LA FIBRE AVEC UN ETAT DE POLARISATION ORTHOGONAL SUBISSENT UN RETARD DE PHASE DE 2P L'UN PAR RAPPORT A L'AUTRE SOIT D'ENVIRON 1CM AU MOINS.

ACOUSTO-OPTIC VARIABLE ATTENUATOR WITH ACTIVE CANCELLATION OF BACK REFLECTIONS

An acousto-optic filter includes an optical fiber with a first region and a second region. A first acoustic wave generator is coupled to optical fiber. The first acoustic wave generator produces a first acoustic wave that travels in a first direction in the first region. A backward-propagating wave is generated in response to propagation of the first acoustic wave along the optical fiber. The backward-propagating wave travels in an opposite direction relative to the first acoustic wave. A first acoustic wave propagation member is coupled to the optical fiber. A second acoustic wave generator is coupled to the optical fiber at the second region. The second acoustic wave generator produces a second acoustic wave that combines with the backward propagating acoustic wave.

ACOUSTO-OPTIC DEVICES UTILIZING LONGITUDINAL ACOUSTIC WAVES

An acousto-optic filter includes an optical fiber with a longitudinal axis, a core and a cladding in a surrounding relationship to the core. The optical fiber has multiple cladding modes. At least one acoustic wave generator is included and made of a sufficiently high frequency piezoelectric material to produce a longitudinal acoustic wave. An acoustic wave propagation member has proximal and distal ends. The distal end is coupled to the optical fiber and the proximal end is coupled to the acoustic wave generator. The acoustic wave propagation member propagates the longitudinal acoustic wave from the proximal to the distal ends and excites the longitudinal acoustic wave in the optical fiber.

Stress-optical phase modulator and modulation system and method of use

A stress-optical phase modulator and modulation system, and method of use of the same is described. The stress-optical phase modulator comprises a source for providing optical beams, a photoelastic optical material, and a means for applying mechanical force to the optical material. The mechanical force so applied creates a uniform stress within the optical material and results in a change in its index of refraction. An optical beam passing through the stressed optical material undergoes a phase change and is recovered as a phase modulated optical beam. Components may be added to the stress-optical phase modulator to produce temperature-compensated and intensity-modulated optical beams.

Method and apparatus for radiant energy modulation in optical fibers

Radiant energy is caused to modulate in phase and frequency in a single mode optical fiber by means of a relatively movable, spatially periodic perturbation.

Laser communication system with wide band magnetrostrictive modulation

A laser beam conducted through an optical fiber cable is phase modulated for communication purposes by a signal encoder operative through a source of current to generate a modulated magnetic field applied to a magnetrostrictive sheathing. The magnetostrictive sheathing is annealed and covers a portion of the fiber cable which undergoes dimensional change to effect modulation.

External modulator for optical communication

PCT No. PCT/JP93/00148 Sec. 371 Date Dec. 23, 1993 Sec. 102(e) Date Dec. 23, 1993 PCT Filed Feb. 5, 1993 PCT Pub. No. WO93/22706 PCT Pub. Date Nov. 11, 1993.In an external modulator for optical communication, a piezoelectric element section is formed by laminating a lower electrode, a piezoelectric thin film and an upper electrode in this order on one surface of a substantially flat substrate which has substantially the same acoustic impedance as the clad layer of a single mode optical fiber to be disposed on the substrate. At least one single mode optical fiber is disposed on the other surface of the substrate on the upper electrode, and the single mode optical fiber is at least partly coated with a material having an acoustic impedance substantially equal to that of the clad layer in a place in which the single mode optical fiber is disposed.

All-fiber broadband polarization combiner

An all-fiber broadband polarization combiner is disclosed based on a Mach-Zehnder (MZ) structure. The entry coupler to the MZ is a polarization pump combiner (PPC) and the exit coupler is a wavelength division multiplexer (WDM) coupler. The two couplers are interconnected with two standard SM fibers which form the arms of the central zone of the MZ. Two polarization maintaining (PM) fibers are spliced to the two input arms of the PPC and are oriented so that polarization X in one PM fiber is orthogonal to polarization Y in the other PM fiber. And the MZ is induced with a phase shift Deltaphi of pi between the two arms of the central zone.

Method and apparatus for phase modulating a fiber-optic rotation sensor

A method for phase biasing a fiber-optic SAGNAC rotation sensor is disclosed comprising the inclusion near one end of the sensing coil (32) of a phase modulator consisting of a second coil (12) of fiber free to rotate independently of the sensing coil (32). The modulator coil is made to oscillate (52) and the desired phase difference modulation is produced by means of the SAGNAC effect in the oscillating coil. Two novel modulator drivers are disclosed. Both have a rigid support hub having radially extending spokes which bend in mechanical synchronism in response to a piezoelectrically induced motive force. The optical fiber is wrapped like a rim around the outside of the spokes for being rotated in an oscillatory manner to effect the desired phase difference modulation.

ОПТОВОЛОКОННЫЙ ИНТЕРФЕРОМЕТР И ОПТОВОЛОКОННЫЙ ПЬЕЗОЭЛЕКТРИЧЕСКИЙ ПРЕОБРАЗОВАТЕЛЬ

Изобретение относится к технической физике, в частности к классу устройств для исследования внутренней структуры объектов, и может быть использовано в медицине для диагностики состояния отдельных органов и систем человека, в частности для оптической когерентной томографии, и в технической диагностике, например, для контроля технологических процессов. Настоящее изобретение направлено на создание оптоволоконного интерферометра, позволяющего при использовании его в составе устройства для оптической когерентной томографии исследовать на достаточную глубину среды, для которых характерное время изменения характеристик или положения относительно оптического зонда мало, например, как при исследовании тканей in vivo. Настоящее изобретение также направлено на разработку оптоволоконного пьезоэлектрического преобразователя, пригодного для использования в оптоволоконном интерферометре для обеспечения необходимой глубины сканирования упомянутых сред. В разработанном оптоволоконном интерферометре оптоволоконный ...

OPTISCHE VORRICHTUNG

Leitungsinternes Lichtleiterfaser-Bandpaßfilter und die Verwendung eines solchen Bandpaßfilters als Dämpfungsglied

Variable Lichtwellenfunktionsschaltung und variables Lichtwellenfunktionsgerät

POLARISATIONSVERWUERFLER.

The polarisation scrambler uses a series of controlled optical delay elements (1,2,3) coupled to a control device providing respective control frequencies (f1,f2,f3) for periodic variation of each delay element (1,2,3). The scrambler may use linear or circular delay elements, or both, with the period duration of the control frequencies (f1,f2,f3) and their difference frequencies less than the mean time interval required for measuring the attenuation of a monomode optical fibre. Two linear delay elements may be used with an angle of between 25 and 65 degrees between their main axes.

DUAL POLARIZATION QUADRATURE MODULATOR

A dual polarization quadrature modulator includes an input planar lightwave circuit (PLC) configured to deliver coherent light to a polymer-on substrate device including a plurality of electro-optic (E-O) polymer optical modulation waveguides configured to each phase modulate the coherent light, and the E-O polymer optical modulation waveguides output modulated coherent light to an output PLC configured to combine waveguide pairs of phase modulated light into Mach-Zehnder interferometric signals, combine pairs of Mach-Zehnder interferometric signals into quadrature modulated signals. A polarization rotator rotates modulated light from one of the quadrature modulated signals into an orthogonal polarization. The output PLC combines the quadrature-modulated and rotated quadrature modulated light to form a dual polarization, quadrature modulated light signal. The PLCs and the polymer-on-substrate device are integrated onto a single assembly substrate. 1. An optical modulator , comprising:an input planar lightwave circuit (PLC) configured to divide and deliver coherent light through a plurality of input interface waveguides;a thin film polymer on substrate (TFPS) modulator including a plurality of electro-optic (E-O) polymer waveguides, each respectively operatively coupled to receive the divided coherent light from each of at least a portion of the plurality of input interface waveguides, at least a portion of E-O polymer waveguides being configured to modulate the received coherent light; andan output planar lightwave circuit including a plurality of output interface waveguides, at least a portion of which are operatively coupled to receive modulated light from the plurality of electro-optic polymer waveguides, the output planar lightwave circuit being configured to combine the received modulated light into at least one output waveguide.2. The optical modulator of claim 1 , wherein the thin film polymer on substrate modulator includes a plurality of first phase bias ...

Stress-Optic Phase Shifter Array for Lidar and Other Applications

An optical element for transmitting a light beam includes a waveguide configured to transmit the light beam from an input end to an output end and having an optical property that can be modified by deformation of the waveguide. A phase-shifter is affixed to the waveguide and is operable in response to a control signal to mechanically deform the waveguide sufficient to induce a phase shift in the light beam transmitted therethrough. The phase-shifter can include a PZT layer. 1. An optical element for transmitting a light beam comprising:a waveguide configured to propagate the light beam from an input end to an output end, said waveguide having an optical property that can be modified by deformation of said waveguide; anda phase-shifter affixed to said waveguide, said phase-shifter configured and operable in response to a control signal to mechanically deform or deflect said waveguide in response to a control signal sufficient to induce a phase shift in the light beam propagated therethrough.2. The optical element of claim 1 , wherein said optical property of said waveguide is the refractive index.3. The optical element of claim 1 , wherein said phase-shifter includes a piezo-electric component configured to deform in response to an electrical signal as said control signal.4. The optical element of claim 3 , wherein said piezo-electric component includes:a layer of a piezo-electric material; andtwo electrodes connectable to an electrical source.5. The optical element of claim 4 , wherein said piezo-electric material is selected from lead zirconate titanate (PZT) and aluminum nitride (AlN).6. The optical element of claim 1 , wherein:said waveguide includes a plurality of waveguides separated by an air gap; andsaid phase-shifter includes a plurality of phase-shifters, each affixed to a corresponding one of said plurality of waveguides, and each configured and operable to deform or deflect the respective waveguide in response to a respective control signal.7. The optical ...

Single mode propagation in fibers and rods with large leakage channels

Various embodiments include large cores fibers that can propagate few modes or a single mode while introducing loss to higher order modes. Some of these fibers are holey fibers that comprise cladding features such as air-holes. Additional embodiments described herein include holey rods. The rods and fibers may be used in many optical systems including optical amplification systems, lasers, short pulse generators, Q-switched lasers, etc. and may be used for example for micromachining.

SECURITY SWITCH

The present disclosure relates to optical switching devices and switch modules that are designed for long-term security monitoring of high-value infrastructure access entry points. Embodiments in accordance with the present disclosure include optical switches based on fiber-Bragg gratings whose operating wavelengths are based on the presence or absence of magnetic coupling between an embedded permanent magnet and an external element. By monitoring the spectral position of the operating wavelengths and/or the magnitude of a light signal at the operating wavelengths, the state of the magnetic coupling can be determined and used as an indicator of whether the security switch has been actuated. 1. A switch module comprising:a first fiber-Bragg grating (FBG) portion that includes a first FBG characterized by a first operating wavelength, wherein the first FBG portion has a first length, and wherein the first operating wavelength is based on the first length; anda first magnet that is mechanically coupled with the first FBG portion such that a first motion of the first magnet induces a first change in the first operating wavelength.2. The switch module of further comprising:a second FBG portion that includes a second FBG characterized by a second operating wavelength, wherein the second FBG portion has a second length, and wherein the second operating wavelength is based on the second length;wherein the first magnet is mechanically coupled with the second FBG portion such that the first motion induces a first change in the second operating wavelength; andwherein the second change is equal and opposite to the first change.3. The switch module of further comprising:a pivot assembly that includes a first attachment point and a second attachment point, wherein the pivot assembly is mechanically coupled with the first magnet such that the first motion induces a first rotation of the first and second attachment points about a rotation axis;a third attachment point; anda fourth ...

OPTICAL FIBER ROTARY SQUEEZER POLARIZATION CONTROLLER

An optical fiber rotary squeezer polarization controller, comprising a base, a left bracket and a right bracket respectively mounted at both ends of the base, characterized in that a shaft is rotatably mounted between the left bracket and the right bracket, the shaft having a through channel cut therein lengthwise for placement of an optical fiber, the shaft further being mounted with a squeezing apparatus corresponding to the channel. The present invention has altered the means by which an optical fiber is fixed onto the prior-art polarization controllers and has eliminated the clamps at both ends of the optical fiber. The shaft carries the squeezing apparatus to rotate to any desired angles while the optical fiber remains stationary under the effect of its own tension. As the optical fiber extends outwardly from either end of the shaft, it is restrained by its own tension and, therefore, will not rotate along with the shaft. As a result, the twisting damage to the optical fiber caused by its being fixed at both ends and twisting of the optical fiber when it is spun after squeezed which would otherwise occur in the prior art can be thoroughly eliminated. In the absence of twisting damage, it is not necessary to make a large squeezer polarization controller and, therefore, the volume of the squeezer polarization controller can be reduced. 1. An optical fiber rotary squeezer polarization controller , comprising a base , a left bracket and a right bracket respectively mounted at both ends of the base , characterized in that a shaft is rotatably mounted between the left bracket and the right bracket , the shaft having a through channel cut therein lengthwise for placement of an optical fiber , the shaft further being mounted with a squeezing apparatus corresponding to the channel.2. The optical fiber rotary squeezer polarization controller as claimed in claim 1 , wherein the squeezing apparatus consists of an upper cover claim 1 , an optical fiber clamp and an ...

POLARIZATION-MAINTAINING OPTICAL FIBRE AND PREFORM AND METHOD FOR PRODUCING THE SAME

The invention relates to a method for producing a polarization-maintaining optical fibre, consisting of a core region and stress-generating elements embedded in the fibre body, having the following method steps: producing a core preform for the core region using internal deposition on a substrate tube, the internally coated substrate tube subsequently being collapsed, generating recesses on the core preform by virtue of the material on the outer surface of the core preform being removed parallel to the longitudinal axis of the core preform at diametrically opposed positions, filling the recesses with stress-generating rods, with the tightest possible rod packing, in a freely selectable first filling geometry, possibly filling the recesses in addition with non-stress-generating rods in a second filling geometry, sheathing the filled core preform with a jacketing tube, preparing the sheathed core preform for a fibre-drawing process, and drawing the sheathed arrangement to form in the optical fibre. A preform for producing a polarization-maintaining optical fibre contains a core preform, having a core region and a lateral region, and also contains a jacketing tube, which encloses the core preform, as well as stress-generating elements contained in the lateral region, wherein the stress-generating elements are provided in the form of recesses in the lateral region, wherein the recesses are filled with doped rods and/or undoped rods, and wherein the rod filling forms a first and/or a second arrangement geometry. 12. A method for producing a polarization-maintaining optical fiber , consisting of a core region and stress applying parts () embedded in the fiber body , comprising the following method steps:{'b': '6', 'producing recesses () in the form of circular sectors on the cross-sectional area of a core preform by removing the material on the outer surface in parallel to the longitudinal axis of the core preform at positions located diametrically opposite to one another ...

Polarization Maintaining Optical Fiber With Non-Symmetric Stress Applying Parts

Embodiments are directed to an optical fiber cable assembly. The optical fiber cable assembly is a polarization maintaining optical fiber assembly. The assembly includes an optical core located within a cladding. Also within the cladding is a stress rod. The stress rod can be centered within the cladding, with the optical fiber eccentrically located within the cladding. There can also be a second optical fiber eccentrically located within the cladding. The optical fiber can be centered within the cladding, with the stress rod eccentrically located within the cladding. 1. A device for transmitting information via light signals comprising:a cladding;an optical core centered within the cladding; anda single stress rod eccentrically located within the cladding; where the cladding contains only one stress rod.2. The device of claim 1 , wherein the single stress rod is configured to maintain a polarization of light traversing through the optical core by applying stress to the optical core.3. The device of further comprising:a buffer surrounding the cladding; anda jacket surrounding the buffer.4. The device of claim 1 , wherein the stress rod is a polarization maintaining and absorption reducing fiber.5. The device of claim 1 , wherein the stress rod has a bow-tie shape.6. The device of claim 1 , wherein the optical core comprises a silica glass.7. The device of claim 1 , wherein:the optical core has a refractive index that is lower than a refractive index of the cladding; and the refractive index of the cladding is lower than a refractive index of the stress rod.8. The device of claim 1 , wherein the device is an optical fiber cable assembly.9. A device for transmitting information via light signals comprising:a cladding;a first optical core eccentrically located within the cladding; anda single stress rod centered within the cladding, where the cladding contains only one stress rod.10. The device of claim 9 , wherein the single stress rod is configured to maintain a ...

Communication apparatus

A communication apparatus includes an optical fiber along which radiation can be transmitted; an optical fiber grating formed within the optical fiber, the optical fiber grating having a structure, and configured to reflect radiation at a particular wavelength; and an instrument coupled to the grating and configured to controllably modify the structure of the grating, thereby changing the wavelength at which the grating reflects radiation. A communication system including the communication apparatus is also described, along with a method of communicating a signal.

Fiber-based multi-resonator optical filters

Optical filters comprising one or more optically-coupled Fabry-Perot resonators are disclosed. In some embodiments, the one or more optically coupled Fabry-Perot resonators include a graded index fiber. In some embodiments, the one or more optically coupled Fabry-Perot resonators are coupled end-to-end, whereas in other embodiments the one or more optically coupled Fabry-Perot resonators are side-coupled through evanescence. One or more implementations of an optical filter allow a spectral response of an input light beam to be controlled, through various approaches, e.g., by exposing a component fiber to ultra-violet radiation. 1. An optical device , comprising:a first fiber Fabry-Perot resonator comprising a first fiber segment, a first reflector formed on a first end facet of the first fiber segment and a second reflector formed on a second end facet of the first fiber segment; anda second fiber Fabry-Perot resonator optically coupled to the first fiber Fabry-Perot resonator, the second fiber Fabry-Perot resonator comprising a second fiber segment oriented to be parallel to the first fiber segment and located to have a portion that spatially overlaps with part of the first fiber segment and is optically evanescently coupled via sides of the first and second fiber segments to the first fiber segment, a third reflector formed on a first end facet of the second fiber segment and a fourth reflector formed on a second end facet of the second fiber segment, wherein a position of the second fiber segment can be shifted relative to the first fiber segment to adjust an interaction length for evanescent coupling between the first and second fiber segments.2. The device as in claim 1 , wherein the first fiber segment is a single-mode fiber segment.3. The device as in claim 1 , wherein the first fiber segment is a multi-mode fiber segment.4. The device as in claim 1 , wherein the first fiber segment is a single-mode gradient index fiber segment.5. The device as in claim 1 , ...

A small-diameter polarization maintaining optical fiber

Disclosed is a small-diameter polarization maintaining optical fiber, which relates to the field of special optical fibers. The small-diameter polarization maintaining optical fiber comprises a quartz optical fiber (); the periphery thereof is provided with an inner coating () and an outer coating (); the interior of the quartz optical fiber () is provided with an optical fiber core layer () and a quartz cladding (); two stress zones () are arranged between the optical fiber core layer () and the quartz cladding (); a buffer coating () is arranged between the inner coating () and the outer coating (); the periphery of each stress zone () is provided with a buffer layer () which is concentric with the stress zone (); when a working wavelength of a small-diameter polarization maintaining optical fiber is 1310 nm, the attenuation thereof reaches less than 0.5 dB/km, and the crosstalk reaches −35 dB/km; and when the working wavelength of the small-diameter polarization maintaining optical fiber is 1550 nm, the attenuation thereof reaches less than 0.4 dB/km, and the crosstalk reaches −30 dB/km. The optical fiber not only has excellent stability characteristics of attenuation and crosstalk, but also has the excellent stability characteristic of long-term operation, and can provide a better optical fiber ring for research on a high-precision optical fiber gyroscope, thereby laying the foundation for the development directions of miniaturization and high precision of the optical fiber gyroscope. 155685122141241768434. A small-diameter polarization maintaining optical fiber , comprising quartz optical fiber () , the periphery of the quartz optical fiber () is provided with an inner coating () and an outer coating () , the inner of the quartz optical fiber () is provided with an optical fiber core layer () and a quartz cladding () , the quartz cladding () is located at the periphery of the optical fiber core layer (); two stress zones () are provided between the optical ...

Optical fiber fixing structure

An optical fiber fixing structure includes: a cylindrical member; an optical fiber inserted into a hole of the cylindrical member; and a fixing material configured to fix the cylindrical member and the optical fiber, wherein the optical fiber is a polarization maintaining optical fiber having a polarization axis, and a center of the optical fiber is arranged so as to be eccentric to a center of the hole, and an angle formed by an eccentric direction connecting the center of the hole and the center of the optical fiber and the polarization axis is −22.5° to 22.5°, or 67.5° to 112.5°.

OPTICAL MODE FILTER EMPLOYING RADIALLY ASYMMETRIC FIBER

Fiber amplifier and/or mode filter including a linearly birefringent LMA fiber coiled at a radius of curvature over a bend length to differentiate a fundamental optical mode from supported higher-order modes through bending losses. The LMA fiber may be a polarization-maintaining (PM) fiber having a variety of geometrical core shapes and cladding configurations. In some embodiments, the birefringent LMA fiber includes a radially asymmetric core that is angularly rotated over a length of the coiled fiber to ensure bending losses are experienced in orthogonally oriented higher-order modes associated with some orientation relative to the core orientation. In some embodiments, the fiber coiling is two-dimensional with bending occurring only about one axis. In some embodiments, an asymmetric core is pre-spun to a predetermined axial spin profile. In some embodiments, angular rotation of the core is achieved through mechanically twisting an un-spun fiber over a length of the coil. 1. A fiber amplifier , comprising:a light source to produce an optical beam; and the LMA fiber has a radially asymmetric core; and', 'the asymmetric core has an angular rotation about a fiber axis over a bend length having a radius of curvature about an axis of curvature, non-parallel to the fiber axis, to attenuate the higher-order modes more than the fundamental mode through bend losses., 'a linearly birefringent large mode area (LMA) fiber coupled to the light source to support a fundamental mode and higher-order modes of the optical beam, wherein2. The fiber amplifier of claim 1 , wherein:the axis of curvature is orthogonal to the fiber axis over the bend length; andthe angular rotation over the bend length has a predetermined spin profile providing a suppression of at least 10 dB/meter of bend length for all higher-order modes.3. The fiber amplifier of claim 2 , wherein the LMA fiber is coiled about the axis of curvature with a fixed radius of curvature over the bend length and a rate of the ...

Integrated-Optics-Based Stress-Optic Phase Modulator and Method for Forming

A phase controller for controlling the phase of a light signal in a surface waveguide and a method for its fabrication are disclosed. The phase controller controls the phase of the light signal by inducing stress in the waveguide structure, thereby controlling the refractive indices of at least some of its constituent layers. The phase controller includes a phase-control element formed on topographic features of the top cladding of the waveguide, where these features (1) provide a shape to the phase-control element that matches the shape of the mode field of the light signal and (2) give rise to stress-concentration points that focus and direct induced stress into specific regions of the waveguide structure, thereby providing highly efficient phase control. As a result, the phase controller can operate at a lower voltage, lower power, and/or over a shorter interaction length than integrated-optic phase controllers of the prior art.

Stress-tuned planar lightwave circuit and method therefor

A planar lightwave circuit that can be optically coupled with an external device with low optical loss, while also providing low-power functional control over an optical signal propagating through the PLC is disclosed. The PLC includes a high-contrast waveguide region in a stress-inducing (SI) phase shifter is formed such that it can control the phase of the optical signal. The high-contrast-waveguide region is optically coupled to a low-contrast-waveguide region via a spotsize converter, thereby enabling optical coupling to off-chip devices with low optical loss. Formation of the SI phase shifter in a high-contrast-waveguide region enables improved responsivity and phase control, reduced voltage, and smaller required chip real estate. As a result, the present invention enables lower-cost and higher-performance PLC systems.

WAVEGUIDE WITH COHERENT INTERFERENCE MITIGATION

A pupil-replicating waveguide suitable for operation with a coherent light source is disclosed. A waveguide body has opposed surfaces for guiding a beam of image light. An out-coupling element is disposed in an optical path of the beam for out-coupling portions of the beam at a plurality of spaced apart locations along the optical path. Electrodes are coupled to at least a portion of the waveguide body for modulating an optical path length of the optical path of the beam to create time-varying phase delays between the portions of the beam out-coupled by the out-coupling element. 1. A pupil-replicating waveguide comprising:a waveguide body having opposed surfaces for guiding a beam of image light therebetween;an out-coupling element in an optical path of the beam for out-coupling a plurality of portions of the beam at a plurality of spaced apart locations along the optical path; andelectrodes coupled to at least a portion of the waveguide body for modulating an optical path length of the optical path of the beam to provide time-varying phase delays between different portions of the plurality of portions of the beam out-coupled by the out-coupling element.2. The pupil-replicating waveguide of claim 1 , wherein the out-coupling element and one of the electrodes comprise a same electrically conductive diffraction grating.3. The pupil-replicating waveguide of claim 1 , wherein the waveguide body comprises:a substrate for propagating the beam of image light therein; andan electrically responsive layer disposed between the electrodes and configured to modulate the optical path length of the beam upon application of an electrical signal to the electrodes.4. The pupil-replicating waveguide of claim 3 , wherein the electrical signal comprises voltage claim 3 , and wherein the electrically responsive layer comprises an elastic polymer material deformable by an electrostatic attraction force between the electrodes upon application of the voltage.5. The pupil-replicating ...

Integrated-Optics-Based Stress-Optic Phase Modulator and Method for Forming

A phase controller for controlling the phase of a light signal in a surface waveguide and a method for its fabrication are disclosed. The phase controller controls the phase of the light signal by inducing stress in the waveguide structure, thereby controlling the refractive indices of at least some of its constituent layers. The phase controller includes a phase-control element formed on topographic features of the top cladding of the waveguide, where these features (1) provide a shape to the phase-control element that matches the shape of the mode field of the light signal and (2) give rise to stress-concentration points that focus and direct induced stress into specific regions of the waveguide structure, thereby providing highly efficient phase control. As a result, the phase controller can operate at a lower voltage, lower power, and/or over a shorter interaction length than integrated-optic phase controllers of the prior art.

HEAD-UP DISPLAY SYSTEM AND METHOD FOR CONTROLLING THE SAME

A head-up display system includes a display control component, a polarization conversion member, a birefringent lens component, a scattering component, and a reflecting component; the display control component is configured to alternately output a first to-be-displayed image and a second to-be-displayed image to the polarization conversion member; the polarization conversion member is configured to convert light having different polarization states; the birefringent lens component is configured to image light of a P-polarization state and a S-polarization state; the scattering component is configured to scatter formed images onto the reflecting component, respectively; and the reflecting component is configured to reflect the images to an eye of a user. 1. A head-up display system , comprising: a display control component , a polarization conversion member , a birefringent lens component , a scattering component , and a reflecting component;the display control component is configured to alternately output a first to-be-displayed image and a second to-be-displayed image to the polarization conversion member on the basis of a preset timing;the polarization conversion member is configured to convert light of the first to-be-displayed image into S-polarized light, and convert light of the second to-be-displayed image into P-polarized light to be incident to the birefringent lens component;the birefringent lens component is configured to image the first to-be-displayed image that has been converted into the S-polarized light on the scattering component to form an object surface of a first projection plane, and image the second to-be-displayed image that has been converted into the P-polarized light on the scattering component to form an object surface of a second projection plane;the scattering component is configured to scatter the object surface of the first projection plane and the object surface of the second projection plane onto the reflecting component, ...

Optical device

The invention relates to an optical device ( 100 ) comprising: a waveguide ( 200 ) comprising a core ( 210 ) extending along an axis of symmetry XX′, and encapsulated in a cladding layer ( 220 ), an actuator ( 400 ) with width L a , overlapping the core ( 210 ) and extending along an axis of symmetry YY′ parallel to the axis of symmetry XX′, said actuator ( 400 ) is designed so that when a voltage is applied to it, it imposes a mechanical stress at the core ( 210 ) to modify its refraction index the device being characterised in that the second axis of symmetry YY′ is offset by a lateral offset D from a plane of symmetry of the waveguide ( 200 ) including the first axis of symmetry and perpendicular to the cladding layer ( 220 ), the lateral offset is between 15% and 50% of the width L a .

OPTICAL FIBER ASSEMBLY WITH ENHANCED FILTERING OF HIGHER-ORDER MODES

Optical fiber assemblies for filtering of higher-order modes include a winding support and an optical fiber wound along a winding path on the winding support. The optical fiber is configured to support a fundamental transverse mode and one or more higher-order transverse modes. The optical fiber has a longitudinal fiber axis, a core, a cladding surrounding the core, a transverse cross-section lacking circular symmetry, and a rotation imparted thereto about the longitudinal fiber axis. The rotation and winding of the optical fiber provide stronger attenuation of the one or more higher-order transverse modes as compared to the fundamental transverse mode. In some implementations, the winding path has a non-constant radius of curvature. In other implementations, the optical fiber has a diameter larger than 10 micrometers and at least one stress-applying part arranged in the cladding about the core. Methods perform higher-order-mode filtering. 1. An optical fiber assembly for higher-order-mode filtering , the optical fiber assembly comprising:a winding support; andan optical fiber configured to support a fundamental transverse mode and one or more higher-order transverse modes, the optical fiber having a longitudinal fiber axis, a core, a cladding surrounding the core, a transverse cross-section having at least one characteristic lacking circular symmetry, and a rotation imparted thereto about the longitudinal fiber axis with a spatial repetition period, the optical fiber being wound on the winding support along a winding path having a non-constant radius of curvature, the rotation and winding of the optical fiber providing stronger attenuation of the one or more higher-order transverse modes as compared to the fundamental transverse mode.2. The optical fiber assembly of claim 1 , wherein the winding path comprises a plurality of turns on the winding support claim 1 , each one of the turns comprising at least one first segment having a first length and a first radius of ...

SYSTEM AND METHOD FOR BREAKING TIME-REVERSAL SYMMETRY WITH ACOUSTIC PUMPING OF NANOPHOTONIC CIRCUITS

Systems and methods provide a nonreciprocal nanophotonic modulator. In some examples, the modulator utilizes acoustic pumping, instead of optical pumping with lasers, and is capable of achieving GHz bandwidth. 1. A system , comprising:a resonator;a waveguide coupled with the resonator for guiding a light to the resonator; anda radio frequency drive coupled to the resonator, the radio frequency drive configured to form an acoustic pump of the resonator for breaking time-reversal symmetry for light propagation.2. The system of claim 1 , further comprising an interdigitated transducer connected with the radio frequency drive claim 1 , where the radio frequency drive powers the interdigitated transducer to form the acoustic pump.3. The system of claim 2 , where the interdigitated transducer and the resonator form a phonon-phonon interaction region on the resonator.4. The system of claim 2 , where the interdigitated transducer is provided at an oblique angle in relation to the resonator.5. The system of claim 1 , further comprising grating couplers allowing light to be coupled into the waveguide.6. The system of claim 1 , where the acoustic pump simultaneously breaks orthogonality between optical modes of the resonator while also satisfying a phase matching condition.7. The system of claim 6 , where the acoustic pump comprises a two dimensional acoustic wave.8. The system of claim 1 , where the resonator includes a waveguide including a ridge.9. The system of claim 1 , where the where the resonator further includes a reflector to reflect phonons travelling from the in the acoustic pump back to the resonator.10. The system of claim 1 , where the resonator includes a racetrack shape having two straight sections connected with two curved sections.11. A method claim 1 , comprising:guiding a light to a resonator; anddriving a radio frequency signal to the resonator to form an acoustic pump of the resonator to break time-reversal symmetry for light propagation.12. The method ...

POLYMER-COATED HIGH-INDEX WAVEGUIDE FOR ACOUSTIC SENSING

Apparatus is provided including an acoustic sensor () having an optical waveguide (). The optical waveguide () includes a waveguide core () having a waveguide core refractive index and a waveguide core photo-elastic coefficient, and an over-cladding layer () coupled to the waveguide core () and including an optically transparent polymer having an over-cladding refractive index and an over-cladding photo-elastic coefficient. The waveguide core refractive index is greater than the over-cladding refractive index, and the over-cladding photo-elastic coefficient is greater than the waveguide core photo-elastic coefficient. Other applications are also described. 1. Apparatus comprising: 'an over-cladding layer coupled to the waveguide core and comprising an optically transparent polymer having an over-cladding refractive index and an over-cladding photo-elastic coefficient;', 'a waveguide core having a waveguide core refractive index and a waveguide core photo-elastic coefficient;'}, 'an acoustic sensor comprising an optical waveguide, the optical waveguide comprisingwherein the waveguide core refractive index is greater than the over-cladding refractive index, and the over-cladding photo-elastic coefficient is greater than the waveguide core photo-elastic coefficient.2. The apparatus according to claim 1 , wherein the over-cladding layer comprises a bisbenzocyclobutene (BCB) over-cladding layer.3. The apparatus according to claim 1 , wherein the waveguide core refractive index is at least 1.7.4. The apparatus according to claim 1 , wherein a maximum magnitude of the photo-elastic coefficient of the waveguide core is 20 TPa.5. The apparatus according to claim 1 , wherein the over-cladding refractive index is lower than 1.7.6. (canceled)7. The apparatus according to claim 1 , wherein the over-cladding photo-elastic coefficient is at least four times greater than the waveguide core photo-elastic coefficient.8. The apparatus according to claim 1 , wherein the optically ...

SINGLE MODE PROPAGATION IN FIBERS AND RODS WITH LARGE LEAKAGE CHANNELS

Various embodiments include large cores fibers that can propagate few modes or a single mode while introducing loss to higher order modes. Some of these fibers are holey fibers that comprise cladding features such as air-holes. Additional embodiments described herein include holey rods. The rods and fibers may be used in many optical systems including optical amplification systems, lasers, short pulse generators, Q-switched lasers, etc. and may be used for example for micromachining. 1. An optical fiber for propagating at least one lower order mode having a wavelength λ , while limiting propagation of higher order modes having a wavelength λ by providing said higher order modes with a higher loss than said at least one lower order mode at said wavelength λ , said optical fiber comprising:a first cladding region comprising a plurality of holes having a diameter, d, and a center-to-center spacing, Λ, wherein the ratio d/Λ is larger than 0.4 and less than about 0.9; anda core region surrounded by said first cladding region, said plurality of holes of the first cladding region configured to substantially confine propagation of said at least one lower order mode to said core region,wherein said core region has a width of at least 20 micrometers and the outside diameter of said optical fiber is at least 200 micrometers,wherein said optical fiber comprises stress elements that are incorporated into at least some of the plurality of holes of the first cladding region, and which generate two-dimensional asymmetries and provide birefringence so that a polarization-maintaining effect for the optical fiber is obtained.2. The optical fiber of claim 1 , wherein said core and first cladding regions are in a substantially optically transmissive main body of said optical fiber claim 1 , said main body comprising material substantially optically transmissive at said wavelength λ claim 1 , said main body having a width and thickness at least about 250 μm so as to reduce mode coupling ...

WAVEGUIDE WITH COHERENT INTERFERENCE MITIGATION

A pupil-replicating waveguide suitable for operation with a coherent light source is disclosed. A waveguide body has opposed surfaces for guiding a beam of image light. An out-coupling element is disposed in an optical path of the beam for out-coupling portions of the beam at a plurality of spaced apart locations along the optical path. Electrodes are coupled to at least a portion of the waveguide body for modulating an optical path length of the optical path of the beam to create time-varying phase delays between the portions of the beam out-coupled by the out-coupling element.

CHANGING PULSE WIDTH TO REDUCE VISIBLE INTERFERENCE

In an optical system that includes a coherent light source and an optical waveguide, a pulse width used by the optical waveguide to project image frames on a display is changed on a frame-by-frame basis. By changing the pulse width for each image frame, the locations and characteristics of visible interference patterns on the display are changed for each successive image frame. Changing the interference patterns for each image frame may result in the interference patterns being less detectable to a viewer. The change in pulse width for each image frame may be fixed or dynamic, and may be made in response to interference patterns being detected on the display. 1. A system for reducing visible interference associated with coherent light sources , the system comprising:an optical waveguide;a coherent light source; and receive a first image frame;', 'cause the coherent light source to project the first image frame into the optical waveguide using a first pulse width;', 'detecting an interference pattern in the first image frame;', 'receive a second image frame; and', 'cause the coherent light source to project the second image frame into the optical waveguide using a second pulse width, wherein the first pulse width is different than the second pulse width and is selected based on the interference pattern detected in the first image., 'an interference engine configured to2. The system of claim 1 , wherein the interference engine is further configured to select a difference between the first pulse width and the second pulse width.3. The system of claim 1 , wherein the coherent light source comprises a laser.4. The system of claim 1 , wherein the system is part of a head mounted display device.5. The system of claim 1 , wherein the interference engine is further configured to detect interference in the projected first image frame claim 1 , and in response to the detection claim 1 , cause the coherent light source to change pulse width used by the coherent light source by ...

Aligning guide using pressure-sensitive index change elastomer

An optical interconnect can be located between a first optical guide with a first optical guide end and a second optical guide with a second optical guide end. The first optical guide and the second optical guide can each have an operational wavelength, which can be substantially the same such that light of such a wavelength can propagate through the optical interconnect. The optical interconnect can include a pressure-sensitive material with a first region with a first refractive index at the operating wavelength. The pressure-sensitive material can include a second region with a second refractive index at the operating wavelength located between the first optical guide end and the second optical guide end. The second region can be induced by a mechanical pressure applied between the first guide end and the second guide end.

Piezoelectric optical switch device

A piezoelectric optical switch includes a planar Mach-Zehnder optical device having a piezoelectric rib disposed on one or both of the waveguide structures. The piezoelectric rib deforms the waveguide structure creating a strain vector that alters the optical path of the waveguide. The piezoelectric rib is offset from the propagation path in the waveguide. This yields several important advantages. By positioning the piezoelectric rib away from the waveguide, the strain components in the propagation path of the waveguide in the directions perpendicular to the direction of propagation, e.g., in the x-direction and the y-direction, are negligible. Since strains in these directions create birefringence, elimination of these strains will minimize the birefringence. The elimination or reduction of birefringence is greatly desired because birefringence degrades the extinction ratio at the outputs of the Mach-Zehnder device. Thus, the piezoelectric switch of the present invention provides a high extinction ratio and a low power consumption and small switching time expected of piezoelectric devices.

Piezoelectric-optic switch and method of fabrication

A piezoelectric-optic switch and method of fabrication therefor is provided. The switch includes a Mach-Zehnder interferometer having a pair of waveguides disposed in a planar substrate, and strips of piezoelectric material such as PZT disposed on a top surface of the substrate over each of the waveguides. The PZT material is electrophoretically deposited on the substrate to a thickness of between 10 and 20 microns and sintered, resulting in a high density on the order of 8 gm/cm 3 . The PZT strips deform the planar substrate surrounding the waveguides to an extent necessary to adjust the phase between optical signals transmitted through the waveguides, which in turn allows an optical coupler connected to the output of the waveguides to effect a signal cross-over.

Optical stress phase modulator based on integrated optics

본 발명은 표면파 도파로(Surface Waveguide) 내의 광 신호의 위상을 제어하기 위한 위상 제어기(Phase Controller) 및 이를 만드는 방법에 관한 것이다. 위상 제어기는, 도파로 구조 내에 응력을 유도하여 광 신호의 위상을 제어함으로써, 적어도 일부의 해당 구성 레이어의 굴절률을 제어할 수 있다. 위상 제어기는 도파로의 상부 클래딩의 토포그라피 특징 상에 형성된 PC(Phase-control) 요소를 포함한다. 이 같은 토포그라피 특징은 (1) 광 신호의 모드 필드(Mode Field)의 모양에 매칭되는 PC 요소로 모양을 변경하고 (2) 응력 집중점(Stress-concentration Point)이 도파로 구조의 특정 영역으로, 유도된 응력을 집중시키고 겨냥하도록 함으로써, 매우 효율적인 위상 제어를 가능케한다. 그 결과, 위상 제어기는 종래의 기술의 집적 광학 위상 제어기에 비해 저전압, 저전력, 및/또는 더 짧은 상호작용 길이에서도 작동할 수 있다.

Acousto-optic fiber-optic frequency shifter and shifting method using periodic contact with a surface acdustic-wave

내용 없음. No content.

Head-up display system and control method thereof

本发明提供了一种抬头显示系统及其控制方法，涉及显示技术领域。本发明通过偏振转换元件进行不同偏振态光线的转换，并利用了双折射透镜组件对S偏振态和P偏振态的光线起成像作用的特性，以及散射组件的散射作用，实现了同时显示第一投影面和第二投影面的图像，通过两个投影面图像的深度融合实现了光场显示，能为驾驶员提供在一定深度范围内的眼部聚焦调节，呈现自然的3D图像，使得显示的图像更逼真，避免驾驶员长期观看产生的眼部疲劳。

Acousto-optic frequency shifter

내용 없음.

Method and apparatus for measuring rotational speed with a sanitary interferometer

Hydrohoning

Fiber optic modal coupler

내용 없음. No content.

A method for producing a polarization-maintaining optical fiber, preform for producing a polarization-maintaining optical fiber and polarization-maintaining optical fiber

Die Erfindung betrifft ein Verfahren zur Herstellung einer polarisationserhaltenden Lichtleitfaser, bestehend aus einem Kernbereich und in dem Faserkörper eingebetteten spannungserzeugenden Elementen mit folgenden Verfahrensschritten: Fertigen einer Kernpreform für den Kernbereich unter Anwendung einer Innenabscheidetechnik auf einem Substratrohr mit einem anschließenden Kollabieren des innenbeschichteten Substratrohres, Erzeugen von Aussparungen auf der Kernpreform durch ein Entfernen des Materials auf der Außenfläche der Kernpreform parallel zur Längsachse der Kernpreform an diametral zueinander gelegenen Positionen, Auffüllen der Aussparungen mit spannungserzeugenden Stäbchen in einer dichtestmöglichen Stäbchenpackung in einer frei wählbaren ersten Ausfüllgeometrie, Gegebenenfalls ergänzendes Auffüllen der Aussparungen mit nicht spannungserzeugenden Stäbchen in einer zweiten Ausfüllgeometrie, Ummanteln der aufgefüllten Kernpreform mit einem Jacketingrohr, Vorbereiten der ummantelten Kernpreform für einen Faserziehprozess, Ziehen der ummantelten Anordnung zur Lichtleitfaser. Eine Preform zur Herstellung einer polarisationserhaltenden Lichtleitfaser enthält eine Kernpreform mit einem Kernbereich und einem Mantelbereich sowie ein die Kernpreform umgebendes Jacketingrohr, sowie im Mantelbereich enthaltene spannungserzeugende Elemente, wobei die spannungserzeugenden Elemente in Form von Aussparungen des Mantelbereichs ausgebildet sind, wobei die Aussparungen mit dotierten Stäbchen und/oder undotierten Stäbchen aufgefüllt sind, wobei die Füllung der Stäbchen eine erste und/oder eine zweite Anordnungsgeometrie bildet.

Optical fiber polarization controller

公开了一种光纤偏振控制器，其通过采用由若干短段双折射光纤(110，120)制成的波片而具有紧凑的尺寸。该光纤偏振控制器通过扭绞或转动连接至常规的单模光纤(100)的双折射片(110，120)来控制输入光的偏振状态。

Tunable optical fiber bragg and long period grating

Disclosed is a tunable optical filter which may be used in telecommunications systems. The filter comprises a single mode optical waveguide containing a grating. The resonance wavelength of the filter is changed by changing the boundary condition at the interface between the cladding layer (14) and an additional layer (16) applied to the outer cladding layer surface. This boundary condition is changed by changing the refractive index of the additional layer (16). Means for changing the refractive index of the additional layer (16) include establishing a structural resonance in the additional layer, or forming the additional layer from electro-optic or piezoelectric materials.

Patent DE3205798C2

Fibre-optical sensor and a sensor device containing the former

A fibre-optical sensor is specified in which an external influencing variable acting on the sensor is detected by the fact that it produces a detectable coupling of two modes or polarisations in the fibre. In one illustrative embodiment of the invention (Figure 10), an optical fibre is constructed in one or a number of successive fibre sections in such a manner that a change in the influencing variable, for example pressure, magnetic field or temperature, directly influences the mode coupling in the relevant section. In a second illustrative embodiment, the influencing variable acts in one or a number of successive fibre sections via a means deforming the relevant fibre section in a wave-like manner in a longitudinal direction, the mode coupling in each case only occurring with a particular length of the light guided in the fibre. Thus, the effect of the influencing variable on a fibre-optical sensor having several successive sensor sections can be spatially resolved by evaluating the wavelength at which the mode coupling is changed by the influencing variable. The optical fibre can either have a coaxial fibre structure (Figure 10) having two closely adjacent light-wave-guiding regions, in which the modes coupling with one another are guided in different optical wave guide ranges (1, 3) of the same fibre, or it can be a normal monomode- or multimode-fibre with a single wavelength range in which both modes or polarisations coupled to one another are guided. <IMAGE>

IMPROVEMENTS ON ACCELERATING KNIVES

TRANSMISSION OPTICAL FILTER

FILTRE OPTIQUE DE TRANSMISSION COMPORTANT AU MOINS UN CORPS BIREFRINGENT QUI EST CONSTITUE PAR UNE FIBRE OPTIQUE MONOMODE 41 DONT LA BIREFRINGENCE EST CHOISIE SUFFISAMMENT FAIBLE POUR QUE LA LONGUEUR L A L'INTERIEUR DE LAQUELLE LES FLUX LUMINEUX SE PROPAGEANT DANS LA FIBRE AVEC UN ETAT DE POLARISATION ORTHOGONAL SUBISSENT UN RETARD DE PHASE DE 2P L'UN PAR RAPPORT A L'AUTRE SOIT D'ENVIRON 1CM AU MOINS. TRANSMISSION OPTICAL FILTER INCLUDING AT LEAST ONE BIREFRINGENT BODY WHICH IS CONSTITUTED BY A SINGLE-MODE 41 OPTICAL FIBER WHOSE BIREFRINGENCE IS CHOSEN SUFFICIENTLY LOW SO THAT THE LENGTH OF THE INTERIOR OF WHICH THE LUMINOUS FLOWS PROPAGATE IN THE FIBARONALIZATION AND ORTH IN THE FIBARONALIZATION SUBJECT A PHASE DELAY OF 2P TO ONE RELATIVE TO THE OTHER OF ABOUT 1CM AT LEAST.

Patent FR2474694B1

Optical energy sensor and demodulation system - has etched single mode fibre stretched or compressed by signal energy to change optical path length

The signal energy to be sensed or detected is caused to stretch an etched single mode fibre. An etched single mode fibre is a single mode glass clad fibre whose cladding thickness has been reduced a specific amount so as to lower its strength. The invention provides that, when necessary to maintain the etched single mode fibre's light guiding properties, the portion of the glass clad which was removed is replaced with a plastic material whose optical index is lower than that of the single mode fibre's core material and whose elastic modulus is lower than that of the glass clad which it replaces. Such an etched single mode fibre is more sensitive to stretching or compression because it is weaker. For a given amount of signal energy, a single mode fibre will stretch a greater amount after it has been etched. The sensor is used in a hydrophone array.

Optical energy sensor and demodulation system - has etched single mode fibre stretched or compressed by signal energy to change optical path length

The signal energy to be sensed or detected is caused to stretch an etched single mode fibre. An etched single mode fibre is a single mode glass clad fibre whose cladding thickness has been reduced a specific amount so as to lower its strength. The invention provides that, when necessary to maintain the etched single mode fibre's light guiding properties, the portion of the glass clad which was removed is replaced with a plastic material whose optical index is lower than that of the single mode fibre's core material and whose elastic modulus is lower than that of the glass clad which it replaces. Such an etched single mode fibre is more sensitive to stretching or compression because it is weaker. For a given amount of signal energy, a single mode fibre will stretch a greater amount after it has been etched. The sensor is used in a hydrophone array.

Single mode optical fibre beam modulator - has movable, spatially periodic perturbation using optical grating placed near core

The device for modulating radiant energy in a single mode clad optical fibre comprises a single mode optical fibre having a modulation control zone where the cladding is partially removed or formed with a decreased thickness relative to the remainder of the cladding. An optical grating is also provided. A device is for mounting the optical grating in the control zone with the crests of the optical grating positioned normal to the optical axis of the fibre. A device slides the optical grating relative to the optical fibre to cause a narrow band of the radiant electromagnetic energy in the optical fibre to be modulated in phase and/or frequency.

ELECTRO-OPTICAL MODULATOR DEVICE HAVING OPTICAL FIBER

FIBER OPTIC ATTENUATOR

Method of knitting combination of intermediate products for shorts on circular-knitting machine

A plurality of brief blanks are knitted upon a circular knitting machine. A row of brief blanks are interconnected in side-by-side relationship in the form of a tube. In one embodiment, the tube is slit walewise as it is being knitted upon the machine, followed by coursewise separation. In a second embodiment, following coursewise separation on the machine, a length of tube (including a row of brief blanks) is removed from the machine and then slit walewise. The brief blanks are folded and side- seamed to complete assembly.

All-fiber broadband polarization combiner

An all-fiber broadband polarization combiner is disclosed based on a Mach- Zehnder (MZ) structure. The entry coupler to the MZ is a polarization pump combiner (PPC) and the exit coupler is a wavelength division multiplexer (WDM) coupler. The two couplers are interconnected with two standard SM fibers which form the arms of the central zone of the MZ. Two polarization maintaining (PM) fibers are spliced to the two input arms of the PPC and are oriented so that polarization X in one PM fiber is orthogonal to polarization Y in the other PM fiber. And the MZ is induced with a phase shift .DELTA..psi. of .pi. between the two arms of the central zone.

Electrostrictive fiber modulators

An apparatus modulates the phase of an optical signal. The apparatus includes an optical medium (110) for propagating the optical signal. At least one electrode (130, 132) is positioned in proximity with the medium (110). The electrode induces an electric field within the medium in re-sponse to an AC voltage to produce varia-tions in the index of refraction of the optical medium (110) through the electrostrictive effect. Preferably, the phase of the optical signal is modulated such that polarization components of the optical signal parallel to and orthogonal to the electric field experience an equal phase shift. In certain embodiments, a DC voltage is supplied to the optical medium. Alternatively, the DC voltage within the optical medium may arise from poling the optical medium. Certain embodiments of the present invention include two electrodes positioned on opposite sides of the optical medium. The apparatus is used in an interferometer to form modulation device or switching device.

Magnetostrictive wavelength-shifting devices and optical communication systems comprising same

A programmable and latchable device for wavelength shifting and chromatic dispersion compensating is disclosed. An optical grating such as a Bragg grating, a nonchirped grating, or a linearly or non-linearly chirped grating, is magnetostrictively strained to alter the dispersion compensator characteristics. In a preferred embodiment, a gradient magnetostrictive body is bonded along its length to the fiber grating. In yet another preferred embodiment, a magnetostrictive body is bonded onto the length of the fiber grating, and a gradient generating, programmable and latchable magnet component is placed adjacent the magnetostrictive body. The body is then latchably strained to a desired level by controlling the extent of magnetization in the magnetostrictive material and the magnet so as to induce or enhance chirping characteristics in the grating. Various optical applications using such are disclosed.

Acousto-optical fiber modulator

Akustooptischer Fasermodulator zur Polarisationsmodulation von linear polarisiertem Licht, mit – einer Lichtleitfaser (2), die einen Kern (7) hat, der von einem Mantel (8) umgeben ist, wobei der Mantel (8) der Lichtleitfaser (2) mit einem Schichtsystem, enthaltend ein Material mit piezoelektrischen Eigenschaften (1), in Kontakt steht, wobei das Schichtsystem zwei planare Elektroden (Au1, Au2) enthält, die das Material mit piezoelektrischen Eigenschaften (1) auf jeweils gegenüberliegenden Flächen einschließen, – zumindest eine der Elektroden (Au2) eine Schichtdicke im Bereich von 10 nm bis 100 μm hat und innerhalb des Schichtsystems von außerhalb freiliegend angeordnet ist, und auf dieser Elektrode (Au2) die Lichtleitfaser (2) mit ihrem Mantel (8) befestigt ist, – die Lichtleitfaser (2) entlang einer Gerade (z-Achse) ausgerichtet ist, die parallel zur Symmetrieachse des Faserkerns (7) ist, und diese 90° zur Ausbreitungsrichtung (y-Richtung) einer der durch das piezoelektrische Material (1) induzierten Schallwelle steht, dadurch gekennzeichnet, daß – das Schichtsystem...

Stabilized fiber optic sensor

STABILIZED FIBER OPTIC SENSOR Abstract A fiber optic sensor comprises a length of optical fiber, forming a loop, and a fiber optic directional coupler for optically closing the loop. The loop and coupler form a resonant cavity for light circulating therethrough. A PZT cylinder, about which the fiber loop is wrapped, is utilized to control the total round trip phase delay of the circulating light, and thus, control the intensity of the optical output signal W0. The phase delay is adjusted to a point Z where the optical output signal W0 is at maximum sensitivity to changes in phase. When the fiber loop is exposed to, e.g., acoustic waves, the loop length changes correspondingly, thereby causing the phase delay, and thus, the optical output signal W0 to vary. By detecting variations in output signal intensity, the frequency and intensity of the acoustic waves may be determined. The sensor also includes a feedback system for stabilizing the fiber loop against low frequency thermal drift.

Method for controlling the polarisation of an optical signal and an optical component for polarisation control of light in planar waveguides

FIBEROPTIC PHASE MODULATOR.

Apparatus for polarization-independent optical polarization scrambler and a method for use therein

A technique which provides scrambled states of polarization (SOPs) in an optical fiber (4). Specifically, polarization independence is achieved by wrapping a single optical fiber (4) around each tube in a cascade of separate piezoelectric tubes (PZTs) (10; 10a?, 10b?, 10c?, 10d?, 10e?, 10f?), with random amounts of fixed birefringence (30; 30a?, 30b?, 30c?, 30d?, 30e?, 30f?) separating each tube, where each tube is then separately excited on a time-varying basis. The tubes are arranged in two groups (101?, 102?), of illustratively three tubes each. Each tube in the first group is separately excited by combined frequency/amplitude modulation (20a?, 20b?, 20c?) with illustratively different modulating frequencies and amplitudes. Each tube in the second group is excited at illustratively a constant frequency and voltage (20d?, 20e?, 20f?). The excitation applied to each tube causes geometrical, physical displacement which, in turn, imparts a t ime-varying birefringence to the fibers. This time-varying birefringence produced by each tube perturbs an initial SOP of the light.

All-fiber broadband polarization combiner

An all-fiber broadband polarization combiner is disclosed based on a Mach- Zehnder (MZ) structure. The entry coupler to the MZ is a polarization pump combiner (PPC) and the exit coupler is a wavelength division multiplexer (WDM) coupler. The two couplers are interconnected with two standard SM fibers which form the arms of the central zone of the MZ. Two polarization maintaining (PM) fibers are spliced to the two input arms of the PPC and are oriented so that polarization X in one PM fiber is orthogonal to polarization Y in the other PM fiber. And the MZ is induced with a phase shift .DELTA..psi. of .pi. between the two arms of the central zone.

Fiber optic polarizer with error signal feedback

Dispersion compensation by using tunable nonlinearly-chirped gratings

A nonlinearly chirped fiber grating (1020a) for achieving tunable dispersion compensation, dispersion slope compensation, polarization mode dispersion, chirp reduction in directly modulated diode lasers, and optical pulse manipulation. A dynamical dispersion compensation mechanism can be implemented in a fiber communication system (1001) based on a such a nonlinearly chirped fiber grating (1020a).

Variable wavelength optical device

(57)【要約】 【課題】 構造が簡単で、波長変更動作の信頼度が高く かつ透過中心波長を変化させても光損失変動の少ない波 長可変光デバイスを提供する。 【解決手段】 周期的に媒体の屈折率が変化するグレー ティング部を含む光ファイバとこの光ファイバに光を入 射する光入力部と光ファイバから出射される特定の波長 の光を取出す光出力部と、グレーティング部に応力を付 与する応力付与部とを備え、圧力付与部によりグレーテ ィング部へ付与される圧力を制御して、グレーティング 部において反射される光の波長を変化させて特定の波長 の光を選択する。本発明の波長可変光デバイスはまた、 光方向性結合器又は光サーキュレータを光入出力部に備 えている。グレーティング部の媒体の周期的な屈折率の 変化の波面法線が光ファイバの光伝搬方向に対して傾斜 させ、反射光の一部が光ファイバのコアから外部に放出 されるようにすることもできる。

Fiber Gratings and Fiber Optic Devices Using the Same

광섬유 내에 미세 굴곡을 유도하여 광섬유를 지나는 광의 모드를 다른 모드로 결합시키는 광섬유 격자 및 이를 응용한 광섬유 소자에 대해 개시하고 있다. 본 발명의 광섬유 격자는, 광섬유를 따라 전파되는 광이 서로 다른 모드 사이에 변환을 일으킬 수 있도록 하기 위해, 구부림 또는 단차에 의한 기계적 응력이 외부로부터 가해진 광섬유에, 국소적 가열에 의해 응력이 해소된 복수의 미세 굴곡부들을 그 길이방향으로 형성한 것을 특징으로 한다. 이 광섬유 격자는 광섬유 노치필터, 광섬유 편광기 등에 응용될 수 있을 뿐 아니라, 비대칭적인 모드결합특성을 이용하여 광섬유 파장가변 대역통과필터, 광섬유 주파수 변환기 등에 널리 응용될 수 있다. 또한, 기계적인 강도도 강하고 소자의 안정성도 높기 때문에, 고온에서 오랜 시간이 경과해도 격자특성의 변화에 의한 광섬유 소자의 열화를 방지할 수 있다.

Single mode fiber optic single sideband modulator

A fiber optic frequency shifter includes an optical fiber (24) having two modes of propagation, each with a different propagation velocity, and a coupler for applying time varying stress to the fiber at first and second locations on the fiber, with a predetermined phase relationship between the stress at the two locations. The coupler may include a plurality of discrete coupling elements, such as ridges (84, 86) or driving electrodes (163, 164, 165, 166) and a driver to drive the coupling elements in accordance with driving signals having the predetermined phase difference, or the coupler may include an acoustic wave generator (118, 120, 122) coupled to the fiber (114) for applying to the fiber an actual travelling acoustic wave. With the discrete distributed coupling elements, the frequency of the driving signals and the phase relationship between the driving signals is such as to create a simulated travelling acoustic wave in the fiber (24). The real or apparent travelling acoustic wave in the fiber causes light propagating through the fiber to be coupled from one of the fiber modes to another of the fiber modes, and to cause the coupled light to be frequency shifted relative to the initial light. The wavelength of the real or apparent acoustic wave is approximately equal to an integer multiple of the fiber beat length to cause constructive coupling of the frequency shifted light.

Fiber optical magnetic field sensor using magnetostrictive material

A sensing element of magnetostrictive material associated with an optical fiber of an interferometer arm defining apparatus for detecting magnetic fields. The magnetostrictive material is adhered in close co-extensive adjacency with the optical fiber and in the presence of a magnetic field undergoes responsive longitudinal dimension changes which strains the optical fiber and induces a strain related phase shift in an optically propagating beam in the fiber detectable by interferometry.

Methods and structures for the control of optical waveguide devices by stress

The invention provides polarization state changer and a phase shifter for shifting a phase of an optical signal including a waveguide having a waveguiding region for guiding the optical signal therethrough, a substrate for supporting said waveguide, and means for inducing stress on the waveguiding region for shifting the phase of the optical signal. The stress is induced by MEMS means. The MEMS means are monolithically formed on the substrate and can be actuated by electrostalical force, mechanical force, or tiltable flaps.

Optical polarisation state controllers

Optical fiber for broadband optical devices and optical fiber devices using thereof

The present invention relates to an optical fiber having a normalized frequency applicable to a broadband optical device, and to a broadband, polarization-independent, low-loss optical fiber device made by using the aforementioned optical fiber. The optical fiber of the present invention has a normalized frequency value V, structural parameters of which including a core radius, a core refractive index and a cladding refractive index are adjusted to minimize the beat dispersion between first and second modes in a predetermined frequency range. Various optical fiber devices may be achieved if the aforementioned optical fiber is used along with acoustic wave generating means and a mode dropper or a mode selective coupler.

Interference microscope with tuning type optical resonator into which single mode optical fiber is incorporated and its application to light filtration and spectral diffraction

Fibre optic sensor

A sensor assembly (1) comprises an optical fibre (4) and a transducer (23) arranged to apply transverse strain to a localised portion (24) of the fibre. Birefringence effects induced by the fibre strain are remotely sensed to obtain a signal representative of the transducer input which in turn is connected to a current sensing coil (34) thereby enabling electric current in a conductor (32) to be remotely sensed. The fibre is a metal coated fibre having a metallic jacket (19) enclosing a silica core and doped silica cladding layer. Damage to the fibre and the effects of creep are thereby avoided. The resulting sensor is particularly suited to the measurement of high currents in power distribution systems.

Method for controlling the polarisation of an optical signal and an optical component for polarisation control of light in planar waveguides

By a method for controlling the state of polarisation (SOP) of an optical signal transmitted through an optical waveguide, the waveguide is buried in a planar structure and a plurality of stress-applying films, having variable stress, are placed on the top of the structure. Preferably the stress-applying films comprise materials that have thermal expansion coefficients different from that of the planar structure or comprise materials with piezo-electric properties. In this way it is possible to produce a cascaded series of optical elements with variable linear birefringence in a planar optical waveguide. Moreover according to the invention it is possible, by the method according to the invention, to manufacture optical components having an active polarisation controller.

Acoustooptic modulator for optical fiber waveguides

An acoustooptic modulator is disclosed in which light may be modulated while propagating through an optical fiber waveguide through the use of focussed acoustic waves. The modulator is formed by encircling a portion of the optical fiber waveguide in an optical communications system with an acoustic transducer. Due to the encircling of a portion of the waveguide by the transducer, the acoustic waves which are generated in the optical fiber waveguide material are focussed inwardly to the center so that the energy densities where acoustooptic modulation occurs are high. Therefore, the acoustic driving powers and modulation efficiencies are highly favorable.

Device for tapping radiation from or injecting radiation into single made optical fiber

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Apparatus for polarization-independent optical polarization scrambler and a method for use therein

A technique, specifically apparatus ( 5 ) and an accompanying method, for an optical scrambler and particularly one that provides scrambled states of polarization (SOPs) in an optical fiber ( 4 ). Specifically, polarization independence is achieved by wrapping a single optical fiber ( 4 ) around each tube in a cascade of separate piezoelectric tubes (PZTs) ( 10; 10 a , 10 b , 10 c , 10 d , 10 e , 10 f ), with random amounts of fixed birefringence ( 30; 30 a , 30 b , 30 c , 30 d , 30 e , 30 f ) separating each tube, where each tube is then separately excited on a time-varying basis. The tubes are arranged in two groups ( 10 1 , 10 2 ), of illustratively three tubes each. Each tube in the first group is separately excited by combined frequency/amplitude modulation ( 20 a , 20 b , 20 c ) with illustratively different modulating frequencies and amplitudes. Each tube in the second group is excited at illustratively a constant frequency and voltage (20 d , 20 e , 20 f ) . The excitation applied to each tube causes that tube to exhibit geometrical, physical displacement which, in turn, imparts a time-varying birefringence to light as it passes through that portion of the fiber wound around that particular tube. This time-varying birefringence produced by each tube perturbs an initial SOP of the light provided by that tube from its original pseudo-stationary position as depicted on a Poincaré sphere.

Optical fiber rotation extrusion type polarization controller

本实用新型公开了一种光纤旋转挤压型偏振控制器，包括基座、安装于基座两端的左支架和右支架，所述左支架和右支架之间转动装配有转轴，该转轴沿长度方向贯穿地开设一条用于放置光纤的槽道，所述转轴上还安装有对应于槽道的挤压装置。本实用新型改变了现有挤压型偏置控制器的光纤固定方式，取消了光纤两端的压块。由转轴带动挤压装置旋转到所需要的角度，而光纤在自身张力的作用下并不转动。光纤由于是从转轴两端延伸出去，依靠其自身的拉力并不跟随转轴旋转。从而彻底消除了现有的光纤两端固定所造成的光纤的扭曲损伤以及光纤挤压后旋转的扭曲。由于没有了扭曲损伤，挤压型偏振控制器也就不必做的很大，减小了挤压型偏振控制器的体积。

Evanescent fiber optic pressure sensor apparatus

An apparatus is disclosed for optically sensing pressure using evanescent wave coupling between two fiber optics. A support base with a channel holds the two waveguides, one on top of the other, with the portion of the waveguide having the cladding material removed in the channel. An upper member having a diaphragm is attached to the support base. The diaphragm has a pedestal attached that is in slight contact with one of the waveguides. When pressure is exerted upon the diaphragm, the waveguides are forced closer together thus affecting the amount of evanescent coupling therebetween.

Converting device using an optical fiber

A optical talk set has a talk set including bending means for bending an optical fiber of an optical cable. vibration applying means for applying vibration to the optical fiber, and a light-receiving element for receiving light leaking upon bending of the optical fiber and for converting the light into electricity, a signal transmitting/receiving line having an input/output ter-minal, for enabling transmission of signals to be input to the bending means and the vibration applying means and a signal output from the light-receiving element, and a housing enclosing the converter, the signal transmitting/receiving line, and the light-receiving element. The input/output terminal of the signal transmitting/receiving line is provided so as to be exposed to the outside of the housing, by virtue of which a call can be made without opening the housing, facilitating maintenance, etc. of an optical fiber path.

PZT fiber optic modulator having a robust mounting and method of making same

A piezoelectric fiber optic phase modulator having a mount at a nodal point of the vibratory system of the modulator. The modulator is excited with an electric field applied in a direction parallel to the axis of the modulator or perpendicular to the radial direction of movement of the modulator. In contrast to the mere hollow cylinder modulator of the related art, the modulator of this invention has a web or center structure integral with the inside surface of the cylinder. The modulator here has a rugged mount, low absorption vibration and negligible harmonics at the mount for efficient and high Q functioning, and has rugged electrical connections for dependable operation.

Optical device and method for manufacturing same

L'invention a pour objet un modulateur de phase (100) pour faisceau lumineux comprenant :- un guide d'onde (200) présentant un axe longitudinal (XX), et- un actionneur piézoélectrique (300) configuré pour appliquer une contrainte mécanique au sein dudit guide d'onde (200) en réponse à une polarisation électrique, ledit actionneur (300) comprenant une première partie (301) couvrant un premier côté (201) du guide d'onde(200) et présentant un premier axe de symétrie (XX') essentiellement parallèle à l'axe longitudinal (XX),ledit modulateur de phase (100) étant caractérisé en ce que l'actionneur (300) comprend une deuxième partie (302) couvrant un deuxième côté (202) du guide d'onde (200), ladite deuxième partie (302) présentant un deuxième axe de symétrie (XX") essentiellement parallèle à l'axe longitudinal (XX). The subject of the invention is a phase modulator (100) for a light beam comprising:- a waveguide (200) having a longitudinal axis (XX), and- a piezoelectric actuator (300) configured to apply a mechanical stress to the within said waveguide (200) in response to electrical bias, said actuator (300) comprising a first portion (301) covering a first side (201) of the waveguide (200) and having a first axis of symmetry (XX') substantially parallel to the longitudinal axis (XX),said phase modulator (100) being characterized in that the actuator (300) comprises a second part (302) covering a second side (202) of the guide wave (200), said second part (302) having a second axis of symmetry (XX") essentially parallel to the longitudinal axis (XX).

Single-mode fiber and coupling device with communication system of same structure

通过使导模LP 01 对适当的隧道泄漏[TL]模产生准谐振耦合，光辐射可有效地在单模纤维的中间部位处取出或注入进去。这种耦合由纤维中的光栅来实现。形成光栅的方法是对纤维施加一周期[或准周期]性的调制，或使纤维折射率产生周期[或准周期]性的变化。为使耦合是准谐振的，α rs 必须相当小，典型值小于1dB/cm。适当选择λ[Z]和/或光栅的幅值函数可增加耦合效率。本发明中的装置可作为辐射耦合器及滤波器使用，光折射型的还可作为幅值调制器使用。

Phase modulator, phase modulator assembly, and optical sensor

An optical sensor which uses a phase modulation method capable of precise measurement as a photodetection means. Using the difference of phase variation of light propagating inside a polarization preserving fiber relative to tensile stress, the polarization preserving fiber suitable for a phase modulator (10), a backlight polarization preserving fiber (23), and a coiled polarization preserving fiber optical element (30) is used, and the optical sensor capable of precise measurement is provided.

Method and device for tuning bragg gratings

A method and a device for tuning a Bragg grating in an optical fiber is disclosed. Tuning of the grating is obtained by applying current to at least one longitudinal, internal electrode arranged along the core of the fiber. When current is passed through the electrode, thermal expansion occurs that produces a stress on the fiber core. At the same time, the temperature of the core is increased. This leads to an electrically controlled tuning of the Bragg grating.

Optoacoustic frequency filter

In a tunable optoacoustic filter, a portion of the optical fiber is coiled around and placed at least partially against a rounded shell equipped with at least one longitudinal slit having an emitter and an absorber on both sides of the slit in contact with the shell or the optical fiber. The emitter transmits elastic waves along the shell and therefore along the fiber to the point of absorber. Coiled configuration of the optical fiber along with various positions of emitters and absorbers are presented allowing to widen the functional range of operation of the filter by increasing the usable length of the optical fiber subject to acoustic oscillations. As a result a reflection/conversion coefficient of up to 0.999 and the filtration band of 1-10 kHz are obtainable.

High power fiber optic modulator system and method

An apparatus and method to increase the output power from LiNbO3 MZM style optical intensity modulating without exceeding the optical power damage threshold imposed by LiNbO3 is described. The optical path from a laser source is divided into two paths by a polarization maintaining (PM) coupler. The two paths form a Mach Zender Modulator (MZM) with a LiNbO3 phase modulator in one path and a fiber looped PZT in the other. The LiNbO3 phase modulator imprints an RF signal onto one path of the MZM cavity, while the fiber wrapped PZT is used to control the path length difference between the two optical paths. The two optical paths are recombined in a second PM coupler. The second PM coupler and a 1-2% coupler are used to sample a small portion of the MZM output signal which is fed back to a phase locked loop (PLL) circuit for providing feedback voltage to the fiber wrapped PZT in the second arm of the MZM, and ensures the phase of the signals in the two arms of the MZM are matched to within a fraction of the laser linewidth. The present invention increases the amount of optical power by using a LiNbO3 modulator within a fiber Mach-Zender cavity.

Electrostrictive fiber modulators

An apparatus modulates the phase of an optical signal. The apparatus includes an optical medium (110) for propagating the optical signal. At least one electrode (130, 132) is positioned in proximity with the medium (110). The electrode induces an electric field within the medium in re-sponse to an AC voltage to produce varia-tions in the index of refraction of the optical medium (110) through the electrostrictive effect. Preferably, the phase of the optical signal is modulated such that polarization components of the optical signal parallel to and orthogonal to the electric field experience an equal phase shift. In certain embodiments, a DC voltage is supplied to the optical medium. Alternatively, the DC voltage within the optical medium may arise from poling the optical medium. Certain embodiments of the present invention include two electrodes positioned on opposite sides of the optical medium. The apparatus is used in an interferometer to form modulation device or switching device.

Light source device, analysis device, and light generation method

A wavelength conversion element (130) has a harmonic generation portion (132) and a parametric oscillation portion (134). The harmonic generation portion (132) generates a harmonic of laser light output from a laser light source (110). The parametric oscillation portion (134) generates signal light and idler light from the harmonic generated by the harmonic generation portion (132). Electrodes (131) and a first voltage control portion (133) control the intensity of the harmonic generated by the harmonic generation portion (132). A first FBG (120) and a second FBG (140) cause resonance of signal light output from the parametric oscillation portion (134). A piezo tube (122) and a second voltage control portion (124) change the resonance frequency of the first FBG (120) and the second FBG (140).

Fiber optic modal coupler

A modal coupler, for coupling between modes of an optical fiber, such as between first and second order modes or between orthogonal polarization modes, comprises a single continuous strand of optical fiber (24), and a device (14) including a plurality of coupling surfaces (18) for applying stress to the optical fiber at spaced intervals along the fiber. The stress deforms the fiber and abruptly changes the fiber geometry at the beginning and end of each stressed region. The change in fiber geometry causes coupling of light from the fundamental mode to the second order mode or between polarization modes. Under certain conditions with nonbirefringent fiber the coupler exhibits polarization dependence, and thus, may be utilized as a fiber optic polarizer. In addition, the device couples coherently, and may be used in interferometric systems.

Optical switches and logic gates employing same

Method for controlling the polarisation of an optical signal and an optical component for polarisation control of light in planar waveguides

By a method for controlling the state of polarisation (SOP) of an optical signal transmitted through an optical waveguide, the waveguide is buried in a planar structure and a plurality of stress-applying films, having variable stress, are placed on the top of the structure. Preferably the stress-applying films comprise materials that have thermal expansion coefficients different from that of the planar structure or comprise materials with piezo-electric properties. In this way it is possible to produce a cascaded series of optical elements with variable linear birefringence in a planar optical waveguide. Moreover according to the invention it is possible, by the method according to the invention, to manufacture optical components having an active polarisation controller.

Optical fibre attenuator

Tunable nonlinearly chirped grating