Fiber-integrated photon crystals and systems

Fiber-integrated microlenses and optical fiber bragg grating coupler, and spectrometer and multiplexer assembled with the same

Thermally diffused multi-core waveguide

TEMPERATURE COMPENSATED OPTICAL PRESSURE SENSOR

TEMPERATURE COMPENSATED OPTICAL PRESSURE SENSOR

Embedded optical sensor capable of strain and temperature measurement using single diffraction grating

Embedded optical sensor capable of strain and temp. measurement using single diffraction grating

Optical waveguide embedded light redirecting Bragg grating arrangement

An optical waveguide light tapping arrangement includes an optical waveguide having solid portions that guide light in a first path along a longitudinal axis, with at least one grating region being embedded in the solid portion at a location remote from its end portions. The grating region includes a multitude of grating elements extending with a substantially equal longitudinal spacing at an oblique angle relative to the longitudinal axis to redirect light reaching the grating elements between the first path and at least one second path extending externally of the waveguide at an angle relative to the longitudinal axis that depends on the oblique angle. When light is directed in one of the first and second paths toward the grating region, it is redirected by the grating elements into the respectively other of the second and first paths with attendant in-phase combination in the other path of light having a wavelength within a narrow range around a central wavelength that is in a predetermined relationship to the spacing of the grating elements. The light propagating in the other path can then be captured. The grating elements are formed in the core by exposing the core to an interference pattern of two ultraviolet radiation beams that are symmetrical with respect to a plane extending at the oblique angle relative to the core axis.

Embedded optical sensor capable of strain and temperature measurement using a single diffraction grating

Distributed, spatially resolving optical fiber strain gauge

A distributed, spatially resolving optical fiber strain gauge in which the core of the optical fiber is written with periodic grating patterns effective for transmitting and reflecting light injected into the core. Spectral shifts in the transmitted and reflected light indicate the intensity of strain or temperature variations at positions of the grating corresponding to the associated wavelengths of injected light.

Microwave air-path clearance sensor

A machine having protruding elements 26 and an adjacent abradable seal 18, which move relative to each other, an air-path clearance G between the seal 18 and the elements 26 and an element distance D2 between the sensor 10 and the elements 26, is provided with a sensor 10 which is recessed within the seal 18 by a recess distance D. A clearance/ thickness circuit 14 provides transmitted and reflected microwave signals 30,32 along a coaxial cable 12 having a characteristic impedance, to the sensor 10, which has an impedance substantially matched to the characteristic impedance of the cable 12. The sensor 10 provides the reflected signal 32 which is indicative of the recess distance D when the elements 26 are not in front of the sensor 10 and is indicative of the blade distance D2 between the sensor 10 and the elements 26 when the elements 26 are in front of the sensor 10. The circuit 14 receives the reflected signal 32 and provides electrical signals indicative of the recess distance D and/or the air-path clearance G. Alternatively, the circuit 14 may provide only the recess distance D. The sensor 10 provides such measurements whether or not the machine is operating.

Single polarization fiber and amplifier

A single polarization fiber and/or amplifier includes a non-polarization preserving fiber (10) having a fiber grating tap (12) which has a predetermined length and strength (.DELTA.n/n) and is oriented at a predetermined angle .theta. and has a grating spacing D so as to couple-out of the fiber (10) a predetermined amount of one polarization (24) over a predetermined wavelength range of an input light (16) and pass the other polarization (28) as output light (26), the grating length being substantially the length of the fiber (10). Alternatively, all or a portion of the fiber (10) may be doped to form a polarization sensitive optical amplifier.

Fiber-integrated microlenses and optical fiber bragg grating coupler, and spectrometer and multiplexer assembled with the same

According to the invention, a microlens (30) is assembled on the exterior surface of an optical fiber (20), said optical fiber having a fiber Bragg grating (FBG) (23) constructed in its core (21), in order to focus the light diffracted through the fiber Bragg grating (FBG) (23) onto other fibers or optical devices or to focus the light received on the fiber (20) onto the fiber Bragg grating (FBG) (23). Numerous configurations consisting of one or several microlenses (38, 68), with one or several fibers (20) perform various functions such as coupling or splitting signals, spectrography, delay lines with taps, phase matching by means of time delay, circulation memory, etc. The microlenses can use angle-magnifying prisms and may comprise Fresnel lenses.

Variable optical fiber Bragg filter arrangement

Microwave air-path clearance sensor

Wide band multicore optical fiber

An optical waveguide having a plurality of cores disposed in a common cladding provides an optical fiber with both a wide bandwidth, by minimizing modal dispersion, and a large aperture to enhance light-carrying capacity. Each of the cores is sized to support only the lowest order mode, HE 11 , and the intercore spacing is selected to achieve a required bandwidth. At the same time, the multiple cores provide a large aperture allowing a relatively large amount of light energy emitted from a noncoherent light source to be coupled into the optical fiber. An array factor A f is given which provides design criteria for the intercore spacing by providing an accurate calculation of the pulse spreading with a large number of cores beginning with a simple twin core fiber.

OPTICAL PRESSURE SENSOR WITH TEMPERATURE COMPENSATION

Fiber-integrated microlenses and optical fiber bragg grating coupler, and spectrometer and multiplexer assembled with the same

According to the invention, a microlens (30) is assembled on the exterior surface of an optical fiber (20), said optical fiber having a fiber Bragg grating (FBG) (23) constructed in its core (21), in order to focus the light diffracted through the fiber Bragg grating (FBG) (23) onto other fibers or optical devices or to focus the light received on the fiber (20) onto the fiber Bragg grating (FBG) (23). Numerous configurations consisting of one or several microlenses (38, 68), with one or several fibers (20) perform various functions such as coupling or splitting signals, spectrography, delay lines with taps, phase matching by means of time delay, circulation memory, etc. The microlenses can use angle-magnifying prisms and may comprise Fresnel lenses.

Variable optical fiber bragg filter arrangement

A variable light filtering arrangement (10) includes at least one optical fiber section (11) including a waveguiding core (13), and at least one permanent Bragg grating region (12) in the optical fiber section. The grating region includes a plurality of grating elements constituted by periodic refractive index variations of a predetermined initial periodicity and cumulatively redirecting, of the light launched into the core for guided propagation therein, that having an axial wavelength within a narrow band around a central wavelength that is determined by the periodicity and refractive index variations of the grating elements. At least one of the periodicity and refractive index variations of the grating region is controlledly modified in such a manner as to temporarily change the central wavelength within a predetermined wavelength range.

POLARIZED FIBER LASER SOURCE

In-fiber photonic crystals and systems

One or more photonic crystals 11, 22, 40, 58, 59 are formed directly in the path of light within an optical fiber 13, 23, 42, 56. Light processed by the photonic crystal may be transmitted out of the fiber by means of a lens 48 or it may be measured by a photoresistive device 51, 60. The photonic crystal may be formed in a trench 12 as an array of dielectric rods 16 having one or more selective defects 17, or the crystal may be formed by providing holes 20 directly in the optical fiber. Filling the interstices between rods 16 with non-linear optical material, and subjecting the crystal to a varying electric field applied by electrodes or to a varying optical radiation can produce a tunable photonic crystal within an optical fiber.

Distributed, spatially resolving optical fiber strain gauge

A distributed, spatially resolving optical fiber strain gauge (13) in which the core (19) of the optical fiber (15) is written with periodic grating patterns (16) effective for transmitting and reflecting light injected into the core (19). Spectral shifts in the transmitted and reflected light indicate the intensity of strain or temperature variations at positions of the grating (16) corresponding to the associated wavelength of injected light.

Air path gap sensor

(57)【要約】 【課題】 高性能なエアパス間げきセンサーを提供す る。 【解決手段】 突出する素材と、互に移動可能である隣 り合う摩耗し易いシール１８と、シール１８と素材２６ 間のエアパス間げき１８、およびセンサー１０と素材２ ６間の素材間隔Ｄ２を有する機械は、くぼみ間隔Ｄによ ってシール１８内に配置されるセンサー１０を備えてい る。間げき／厚み回路１４は、特性インピーダンスを有 する同軸ケーブル１２に沿って、本質的にケーブル１２ の特性インピーダンスに適合するインピーダンスを有す る送信および反射マイクロ波信号３０，３２を供給す る。回路１４は、反射信号３２を受信するとともに、く ぼみ間隔Ｄおよび／若しくはエアパス間げきＧを示す電 気信号を供給する。また、回路１４はくぼみ間隔Ｄのみ を供給する。センサー１０は機械が動作しているかどう かの測定も行う。

Fiber-integrated photon crystals and systems

According to the invention, one or several photon crystals (11, 22, 40, 58, 59) are formed directly in the optical path inside an optical fiber (13, 23, 42, 56). The light processed by the photon crystal can be transmitted from the fiber by means of a lens (48), or can be measured with a photo resistor device (51, 60). The photon crystal can be provided in the form of an arrangement of dielectric rods (16) in a trench-shaped recess (12) and may have one or several defects (17), or may be formed by holes (20) provided directly in the optical fiber. By filling the spaces between the rods (16) with a non-linear optical material and exposing the crystal to a variable electric field, said electric field being connected via electrodes, or to variable optical radiation, it is possible to produce a tuneable photon crystal inside an optical fiber. Due to the variety of possible applications for photon crystals and non-linear optical elements as well as photo-sensitive devices, it is also possible to create optical measuring systems in the trench-shaped recess in the fiber using this technology.

Single sideband waveguide modulator

A novel single sideband electro-optic modulator (10) in­cludes a planar waveguide structure (14) allowing only circularly po­larized optical and microwaves to propagate therein with equal phase velocities comprises a strip loaded GaAlAs/GaAs/GaAlAs structure with appropriate microstrip electrodes (16). The present modulator (10) is readily fabricated using established microelectronic fabrication techniques and a modified MOCVD epitaxial growth pro­cess.

Microwave air-path clearance sensor

A machine having protruding elements 26 and an adjacent abradable seal 18, which move relative to each other, an air-path clearance G between the seal 18 and the elements 26 and an element distance D2 between the sensor 10 and the elements 26, is provided with a sensor 10 which is recessed within the seal 18 by a recess distance D. A clearance/ thickness circuit 14 provides transmitted and reflected microwave signals 30,32 along a coaxial cable 12 having a characteristic impedance, to the sensor 10, which has an impedance substantially matched to the characteristic impedance of the cable 12. The sensor 10 provides the reflected signal 32 which is indicative of the recess distance D when the elements 26 are not in front of the sensor 10 and is indicative of the blade distance D2 between the sensor 10 and the elements 26 when the elements 26 are in front of the sensor 10. The circuit 14 receives the reflected signal 32 and provides electrical signals indicative of the recess distance D and/or the air-path clearance G. Alternatively, the circuit 14 may provide only the recess distance D. The sensor 10 provides such measurements whether or not the machine is operating.

Embedded optical sensor for measuring voltage and temperature with a single diffraction grating

SINGLE-POLARIZATION FIBER AND AMPLIFIER.

UNA FIBRA DE POLARIZACION UNICA Y/O UN AMPLIFICADOR INLCUYE UNA FIBRA QUE PRESERVA LA NO POLARIZACION (10) QUE TIEN UNA TAPA ENREJADA EN FIBRA (12) QUE TIENE UNA PREDETERMINADA LONGITUD Y RESISTENCIA ({DL}N/N) Y QEU ESTA ORIENTADA UN ANGULO PREDETERMINADO Y TIENE UN ESPACIO DE ENREJADO D COMO PARA ACOPLAR FUERA DE LA FIBRA (10) UNA CANTIDAD PREDETERMINADA DE UNA POLARIZACION (24) SOBRE UN RANGO PREDETERMINADO DE LA LONGITUD DE ONDA DE UNA LUZ DE ENTRADA (16) Y PASA A LA OTRA POLARIZACION (28) COMO LUZ DE SALIDA (26), LA LONGITUD DE ONDA DEL ENREJADO ES SUBSTANCIALMENTE LA LONGITUD DE LA FIBRA (10). ALTERNATIVAMENTE, TODAS O UNA PARTE DE LA FIBRA (10) PUEDE SER DOPADA PARA FORMAR UN AMPLIFICADOR OPTICO SENSITIVO DE POLARIZACION. A SINGLE POLARIZATION FIBER AND / OR AN AMPLIFIER INCLUDES A FIBER THAT PRESERVES NON-POLARIZATION (10) THAT HAS A FIBER GRIDED LID (12) THAT HAS A DEFAULT LENGTH AND STRENGTH ({DL} N / N) AND IS FOCUSED A DEFAULT ANGLE AND HAS A GRID SPACE D TO COUPLED OUT OF FIBER (10) A DEFAULT AMOUNT OF A POLARIZATION (24) OVER A DEFAULT RANGE OF THE WAVE LENGTH OF AN ENTRY LIGHT (16) AND GOES TO THE ANOTHER POLARIZATION (28) AS OUTPUT LIGHT (26), THE WAVE LENGTH OF THE GRID IS SUBSTANTIALLY THE FIBER LENGTH (10). ALTERNATIVELY, ALL OR A PART OF THE FIBER (10) MAY BE DOPED TO FORM A SENSITIVE POLARIZATION OPTICAL AMPLIFIER.

In-fiber photonic crystals and systems

One or more photonic crystals 11, 22, 40, 58, 59 are formed directly in the path of light within an optical fiber 13, 23, 42, 56. Light processed by the photonic crystal may be transmitted out of the fiber by means of a lens 48 or it may be measured by a photoresistive device 51, 60. The photonic crystal may be formed in a trench 12 as an array of dielectric rods 16 having one or more selective defects 17, or the crystal may be formed by providing holes 20 directly in the optical fiber. Filling the interstices between rods 16 with non-linear optical material, and subjecting the crystal to a varying electric field applied by electrodes or to a varying optical radiation can produce a tunable photonic crystal within an optical fiber.

Temperature compensated optical pressure sensor

Forward scattering laser particulate sensor

Abstract Forward Scattering Laser Particulate Sensor A sensor employs a laser to obtain a colli-mated light beam for transmission across the gas effluent of a catalytic cracking process. Parti-culate matter entrained in the gas flow forward scatters light energy to a collecting aperture which, in turn focuses the scattered light on a first photodetector. A second photodetector receives directly transmitted light energy. A ratio between the output signals of the two photodetectors is derived and presented to a threshold level detector. If the magnitude of the scatter exceeds a predetermined level it is concluded that a catalyst load dump has occurred. The optical system is carefully selected to ensure that only light energy scattered from a sample volume within the entrained gas flow reaches the first photodetector. This is im-portant because it prevents particulate matter on the surfaces of the transparent windows from affecting the operating of the sensor.

Fiber optic strain sensor

UV-trimmed fused tapered couplers

A method of trimming fused-tapered couplers, with or without in-fiber Bragg gratings, to form multiplexers, demultiplexers or combinations of both, by either or both of (1) increasing the phase differential between the symmetric and asymmetric supermodes by irradiating one or both ends of the coupler with UV radiation confined transversely to between the cores of the fibers, and (2) decreasing the phase differential between the modes by irradiating a portion of one or both ends of the coupler with two beams of UV radiation, each confined transversely to include a corresponding core and excluding a significant fraction of the space between the cores.

Thermally diffused multi-core waveguide

A thermally diffused dual-core (TDDC) waveguide is provided that has a pair of spaced cores (12,14) disposed within a cladding (16). The waveguide (10) is formed of a glass material having the appropriate dopants to allow light (15) to propagate in either direction along the cores (12,14). The TDDC waveguide is formed by heating a portion (22) of a dual-core waveguide (10) to symmetrically diffuse the dopants of the cores (12,14) into the cladding (16). Consequently, the optical mode fields of the cores spread beyond the optical mode field of each original core such that optical field in one core (12) excites the optical field in the adjacent core (14) to optically couple the two cores (12,14). The amount of diffusion of the core into the cladding is dependent on the temperature of the heat and the time the heat is applied to the dual-core waveguide. The cores may be diffused so that the cores overlap to thereby create a unitary core. The TDDC waveguide may be used to provide a coupler or wavelocker device.

ACTIVE LASER OPTICAL MULTI-POINT LASER SENSOR

Message transmission system with frequency dividing optical components for parallel processing of optical pulses

The invention relates to a message transmission system with frequency dividi ng optical components. According to the invention, light pulses with different frequencies are coupled out of an optical fibre by means of fibre grating and/or photoionic crystals and imaged by focusing elements outside of the optical fibre. The fibre grating for different frequencies can be arranged in a single period or in different successive periods. The photoionic crystals can be used at the end of the optical fibre or can be etched into a channel or pit in a glass fibre. Additional delay elements ensure that light pulses with different frequencie s are imaged at the same time in a predetermined chosen time ratio, in accordance with a parallel reprocessing stage.

Sensore di sollecitazione a fibre ottiche.

Fiberoptisk spenningsavfoelingsanordning.

Sensore di pressione ottico con compensazione delle variazioni ditemperatura.

Faser-integrierte photonenkristalle und -systeme

Anordning ved overføring og bearbeiding av optiske signaler med forskjellige frekvenser

Einrichtung zur übertragung von optischen signalen unterschiedlicher frequenzen

Einrichtung zur übertragung von optischen signalen unterschiedlicher frequenzen

Faser-integrierte mikrolinsen und optische faser- bragg-gitter-koppler und damit aufgebaute spektrometer und multiplexer

Avfoelingsanordning for mekanisk spenning.

Avfoelingsanordning for mekanisk spenning.

Sensore di sollecitazione in diafonia in fibre ottiche con risoluzione spaziale.

Strumentazione utilizzante componenti in ottica integrata per la diagnostica di parti con sensori a fibra ottica inclusi o fissati sulla superficie.

Aktiver laseroptischer mehrpunkt-lasersensor

Spatially resolving fiber-optic crosstalk strain sensor

Sensore di sollecitazione in diafonia in fibre ottiche con risoluzione spaziale

Strumentazione basata sull'ottica integrata per la diagnostica di parti con sensori a fibra ottica inclusi o fissati sulla superficie.