Including Physical Deformation Or Movement Of Waveguide Patents (Class 385/13)
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Patent number: 6895132Abstract: A fiber optic sensor comprises two independent fibers having Bragg gratings which are coupled to commutating broadband optical sources through splitters and wavelength discriminators. The ratio of detected optical energy in each of two detectors examining the wave intensity returned to a wavelength discriminator coupled with the characteristic of the wavelength discriminator determines the wavelength returned by the grating. In another embodiment, tunable filters are utilized to detect minimum returned wave energy to extract a sensor wavelength Reference to the original grating wavelength indicates the application of either temperature or strain to the grating. In another embodiment, a plurality of Bragg grating sensor elements is coupled to sources and controllers wherein a dimensional change in a fiber having a Bragg grating is detected using a measurement system comprising broad-band sources, optical power splitters, a high-sensitivity wavelength discriminator, optical detectors, and a controller.Type: GrantFiled: April 24, 2003Date of Patent: May 17, 2005Assignee: IFOS, Inc.Inventors: Behzad Moslehi, Richard James Black, Herbert John Shaw, Keiichiro Toyama
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Patent number: 6886977Abstract: A sensor measures temperature in stationary components of electrical machines using fiber optics. An optical fiber is embedded in a non-metallic ribbon. Notches are cut in the ribbon to effect bends that accommodate a shape of a stationary component. The ribbon and optical fiber are attached to the stationary component. A series of laser pulses can be injected from at least one end of the optical fiber, and the stationary component temperature can be monitored by interrogation of reflections from the series of laser pulses.Type: GrantFiled: July 17, 2003Date of Patent: May 3, 2005Assignee: General Electric CompanyInventors: Christopher Anthony Kaminski, Konrad Roman Weeber, Thomas Bonner, Todd Garrett Wetzel, John William Devitt, Veera Palanivelu Rajendran
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Patent number: 6888972Abstract: A multiple component mechanism for housing one or more fiber optic based sensors and one or more fiber organizers and other devices for the sensors is disclosed. The mechanism includes a splice component and a sensor component, which are hermetically sealed. The sensor and splice components include substantially tubular bodies having lids welded to the ends. The fiber organizer and other devices are installed in the cylindrical splice component. The one or more sensors are installed in the tubular body of the sensor component with wedging devices. In one embodiment, the sensor component is acoustically decoupled from the splice component by a tube welded to the lids of the components. The tube communicates optical fiber from the fiber organizer to the one or more sensors.Type: GrantFiled: October 6, 2002Date of Patent: May 3, 2005Assignee: Weatherford/Lamb, Inc.Inventors: Arne Berg, Sverre Knudsen
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Patent number: 6882761Abstract: A small-sized and low-cost silicon platform for optical modules which enables high-speed transmission. A conductor pattern is formed on an oxide layer formed on the surface of a silicon substrate through a dielectric film. A hole extending from the surface of the dielectric film to the oxide layer is formed in the dielectric film at a position for the formation of a bonding pad. A conductor material is directly formed on the oxide layer exposed to the bottom of this hole. This conductor material constitutes a bonding pad portion electrically connected to the conductor pattern.Type: GrantFiled: January 22, 2001Date of Patent: April 19, 2005Assignee: The Furukawa Electric Co., Ltd.Inventors: Takehiko Nomura, Masayuki Iwase
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Patent number: 6878926Abstract: A differential measurement system using pairs of Bragg gratings including at least one optical sensor having two Bragg gratings in two optical waveguides and having sensitivities adjusted so that respective spectra of the two gratings have a relative spectral shift dependent on a parameter or parameters to be measured. The system also includes an optical source to supply light to the two optical waveguides to interrogate them, a mechanism enabling light to pass successively through the two Bragg gratings of the same sensor, photodetectors to measure the power level of light having passed only through one of the two optical waveguides and the power level of light having passed successively through the two optical waveguides, and a processor to process the power levels and supply values of the parameter or parameters measured. The system is applicable in particular to measurements of temperatures, stresses, and pressures.Type: GrantFiled: June 3, 2002Date of Patent: April 12, 2005Assignee: Commissariat a l'Energie AtomiqueInventors: Christophe Martinez, Pierre Ferdinand
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Patent number: 6876786Abstract: An optical fiber sensor system comprising of an optical fiber including plurality of sensitive elements, each sensitive element has characteristic spectral band which in normal undisturbed condition lies in a first wavelength range and, under an influence of some specified condition to be detected, shifts to a second wavelength range; first and second wavelength ranges do not overlap. Means for probing an optical transmission or reflection of the fiber operate within second wavelength range to monitor the changes of the transparency or reflectivity of the fiber caused by the shift of characteristic spectral band into the second wavelength range. The invention provides means for distributed monitoring of equipment or construction structures and detection of specified conditions and can provide alarm signal when the specified conditions become effective.Type: GrantFiled: October 2, 2002Date of Patent: April 5, 2005Assignee: Cicese-Centro de InvestigationInventors: Mikhail Chliaguine, Vassili Spirine, Serguei Miridonov, Francisco Javier Mendieta Jimenez, Enrique Mitrani Abenchuchan
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Patent number: 6873752Abstract: A tuneable sensor reed for fiber optic vibration sensors. A sensor reed is mounted inside of a sensor case with an adjustable mounting structure such as a screw, bolt, clamp or cam lock. Adjusting the mounting structure changes the stresses on the sensor reed, and therefore adjusts the base frequency without the need to replace the whole sensor case. In a particular embodiment, the sensor reed is held in place by screws that completely penetrate the sensor case, and adjustments are made at the terminal end of the screw, which is on the outside of the sensor case, using for example, lock nuts. This adjustment allows for a sensor reed to be reset to its base frequency to compensate for such things as frequency drift, or to be set to a new frequency as desired.Type: GrantFiled: August 8, 2003Date of Patent: March 29, 2005Assignee: Siemens Westinghouse Power CorporationInventor: Charles M. Rowe
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Patent number: 6870975Abstract: A fiber optic sensor includes two reflective elements in series. The first reflective element is formed as a partially mirrored surface on the end of a single-mode optical fiber lead which is bonded into a ferrule. A sleeve is used to join the ferrule to a second ferrule which is turn is bonded to a length of single-mode optical fiber. The second reflective element is a partially mirrored surface on the cleaved end of the second fiber. The second fiber may be affixed to or embedded in a structure to be monitored and changes its optical path length in response to a condition of the structure. Light introduced into the sensor is reflected from the first or second reflective element and thus follows two optical paths. The path length difference between the two optical paths is twice the optical path length of the second fiber.Type: GrantFiled: November 14, 2001Date of Patent: March 22, 2005Assignee: Fiber Optic Systems Technology, Inc.Inventors: W. Don Morison, Gerald Manuelpillai, Roderick C. Tennyson, Thierry Cherpillod, Dominic Rouse
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Patent number: 6868212Abstract: A method for adjusting the wavelength and dominant mode of a laser fiber prior to installation in a laser assembly includes the steps of linearly stretching the laser fiber so as to modify its output wavelength, axially twisting the laser fiber so as to modify its dominant mode, and affixing the laser fiber to a laser assembly in its linearly stretched and axially twisted condition. The laser assembly includes a dynamic tuning mechanism for wavelength adjustment during use. The twisted and stretched fiber has an unadjusted wavelength and dominant mode that are within a selected range before adjustment by the dynamic tuning mechanism.Type: GrantFiled: March 6, 2003Date of Patent: March 15, 2005Assignee: Evans & Sutherland Computer CorporationInventors: Jeannie DeWitte, Yuri Grapov, David Owen, Dennis Elkins, Aaron McAllister, Allen Tanner
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Patent number: 6859583Abstract: A fine-tuning assembly for an optical grating in an optical fiber is provided. The fiber is mounted under tension in a hollow structure which has a sliding member longitudinally slideable therein. The fiber is attached to both the sliding member and hollow structure. A slanted passage is provided in the sliding member, forming a small angle with the transversal, and a wedge member is slideably inserted in this passage. To fine-tune the spectral response of the grating, the wedge member is transversally displaced without any longitudinal displacement, preferably by the action of screws, thereby pushing on its walls to longitudinally slide the sliding member and adjust the tension in the fiber.Type: GrantFiled: February 22, 2002Date of Patent: February 22, 2005Assignee: Teraxion Inc.Inventors: Richard L. Lachance, Andre Vovan
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Patent number: 6856726Abstract: In a light waveguide, the one end of which comprises a flat entering area for the light to be coupled into the core of the light waveguide, the entering area is narrower than the core diameter of the light waveguide and, around the entering area, the end of the light waveguide is laterally sloped up to the entering surface. Only the light which impinges on this entering area passes into the core and is guided therein.Type: GrantFiled: February 9, 2001Date of Patent: February 15, 2005Assignee: Wavetek Wandel Goltermann Eningen GmbHInventor: Thomas Fuhrmann
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Patent number: 6850657Abstract: A capillary waveguide fluorescence sensor which includes a capillary and an optical/fluid connector connected to an end of the capillary. The optical/fluid connector includes a fluid sample injection port for longitudinally injecting a fluid sample into the capillary bore and at least one optical fiber for either longitudinally delivering light energy into the capillary or longitudinally collecting fluorescence emission from the fluid sample injected into the capillary bore. The sensor may also include at least one capillary outer surface collection optical fiber for perpendicularly collecting fluorescence emission from the fluid sample injected into the capillary bore. The capillary outer surface collection optical fiber is positioned adjacent the outer surface of the capillary wall such that the central axis of the collection optical fiber is substantially perpendicular to the central axis of the capillary bore.Type: GrantFiled: February 7, 2003Date of Patent: February 1, 2005Assignee: The Research Foundation of State University of New YorkInventors: Harbans S. Dhadwal, Josephine Y. Aller, Paul F. Kemp
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Patent number: 6838660Abstract: In a preferred embodiment, the invention provides a fiber optic pressure sensor apparatus which includes a light source, a reflective sensor diaphragm movable in accordance with pressure in a medium and an optical fiber coupled to the light source for delivering a first wavefront of light to the reflective sensor diaphragm. The optical fiber has an endface which is separated from the reflective sensor diaphragm by a gap, the endface receiving a second wavefront of light reflected from the reflective sensor diaphragm. The first and second wavefronts constructively and destructively interfere to create a modulated optical signal. A spectrometer is coupled to the optical fiber for converting the optical signal into a series of digital values, and means for analyzing the digital values is provided for obtaining a measurement of the pressure in the medium. An optical coupler is preferably provided for coupling the light source, the optical fiber, and the spectrometer.Type: GrantFiled: June 4, 2001Date of Patent: January 4, 2005Assignee: Airak, Inc.Inventors: Paul Grems Duncan, Sean Michael Christian, John Alan Schroeder
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Patent number: 6836577Abstract: A variable coupler fiberoptic sensor utilizes a coupler having a fused coupling region that can be deflected to change the light distribution to a plurality of output fibers without putting the coupling region under tension. A compact, rugged, and highly sensitive sensor design is achieved by use of a coupler having a fused coupling region arranged substantially in a U-shape to allow the input and output fiberoptic leads to extend from the same side of the sensor structure.Type: GrantFiled: September 20, 2002Date of Patent: December 28, 2004Assignee: Empirical Technologies CorporationInventors: David Gerdt, Martin C. Baruch, Charles Adkins
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Patent number: 6834143Abstract: An optical module comprising: a comb-shaped package having a plurality of teeth portions and a base portion; and at least one optical fiber having fiber grating, wherein respective fiber-grating formed portions of at least one optical fiber are placed in corresponding teeth portions and base portion of said package, and the optical fiber is fixed to the base portion and corresponding teeth portion in such manner that the fiber-grating formed portion exists between the base portion and the corresponding teeth portion.Type: GrantFiled: May 29, 2002Date of Patent: December 21, 2004Assignee: The Furukawa Electric Co., Ltd.Inventors: Atsushi Shinozaki, Takashi Shigematsu, Toshihiko Ota, Shigehito Yodo
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Patent number: 6834142Abstract: An optical filter for filtering a spectral profile of an optical signal for providing an output signal having a desire gain profile, such as a flatten gain profile. The filter comprises an optical waveguide that includes a core disposed within a cladding having an outer dimension greater than 0.3 mm. A Bragg grating is imparted or written in the core of the waveguide that attenuates the received optical input signal in accordance with a defined reflection or transmission filter profile. The Bragg grating may be a slanted grating. The filter profile is complementary to the spectral gain profile of the input signal to provide an output signal having a substantially flat spectral profile of a desired wavelength band. The cladding of the waveguide may have a mechanically advantageous outer geometry (e.g., a “dogbone” shape) for allowing an axial compressive force to tune the Bragg grating.Type: GrantFiled: March 15, 2002Date of Patent: December 21, 2004Assignee: CiDRA CorporationInventors: Timothy J. Bailey, Martin A. Putnam, Jay W. Dawson, Joseph Pinto, James S. Sirkis, Paul S. Szczepanek
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Patent number: 6829415Abstract: A tunable optical waveguide is enclosed in an enclosure containing a controllably moveable region of fluid with a refractive index greater than the optical fiber such that at least a first transmission property of the waveguide is modified when the region of fluid is moved. In a first embodiment, the optical device comprises a Bragg grating that is tuned by moving the fluid over the grating to vary the amplitude of desired wavelengths that are reflected back through the core of the fiber. In a second embodiment, the optical device comprises a long-period grating that is tuned by moving the fluid over the grating to vary the amplitude of desired wavelengths that are transferred into the cladding of the fiber and, as a result, to decrease the amplitude of those desired wavelengths that are transmitted through the core of the fiber.Type: GrantFiled: August 30, 2002Date of Patent: December 7, 2004Assignee: Lucent Technologies Inc.Inventors: Timofei Nikita Kroupenkine, Peter Mach, John A. Rogers, Shu Yang
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Publication number: 20040234187Abstract: A method of measuring nonstationary oscillatory motion of a sample is disclosed. The method comprisesing the steps of illuminating a sample with an illuminating optical fiber; detecting reflectedbackscattered light from the sample with a plurality of detecting optical fibers; coupling each optical fiber of the plurality of detecting optical fibers with a modulating optical fiber; and generating measurements of the nonstationary oscillatory motion of the sample. An apparatus for measuring nonstationary oscillatory motion of a sample is also disclosed. The apparatus comprises a light source; an illuminating optical fiber coupled to the light source; and a plurality of optical fibers positioned around the illuminating optical fiber and coupled to receive reflectedbackscattered light from the sample.Type: ApplicationFiled: April 15, 2004Publication date: November 25, 2004Inventors: Lid B. Wong, Hua Mao, Tarun Chandra, Donovan B. Yeates
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Patent number: 6816638Abstract: A strain sensor comprises an optical waveguide having a plurality of reflecting structure (Bragg grating) along its length. Each structure reflects light at a different characteristic wavelength (&lgr;1 to &lgr;n+1) which changes in dependence on a change of physical length of at least part of the reflecting structure. The reflectivity of reflecting structures which reflect at characteristic wavelengths which are adjacent to each other (&lgr;1 and &lgr;2 or &lgr;n and &lgr;n+1) are configured to be different such that the intensity of light reflected from adjacent structures can be used to discriminate between them.Type: GrantFiled: December 28, 2001Date of Patent: November 9, 2004Assignee: Bookham Technology, PLC.Inventors: Ian Bennion, John Williams, Christopher Groves-Kirkby, Lin Zhang
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Patent number: 6813959Abstract: Disclosed is an apparatus for measuring a residual stress and a photoelastic effect of an optical fiber, which includes: a light source; a rotary type optical diffuser distanced from the light source in a predetermined distance for suppressing the spatial coherence of a light radiated in the light source; an optical condenser for condensing the radiated light passed through the optical diffuser into a spot where the optical fiber is located; a polarizer for polarizing the light passed through the optical condenser into a 45° linear polarized light from an axis of the optical fiber; a polarization analyzer, installed at 90° angle with respect to the polariscope and attached closely with the optical fiber, to prevent the penetration by the background image of the optical fiber; an optical fiber strain unit including a strain sensor for straining the optical fiber on the polarization analyzer toward a longitudinal direction and measuring the strain on the optical fiber; an object lens for magnifying theType: GrantFiled: May 8, 2003Date of Patent: November 9, 2004Assignee: Samsung Electronics Co., Ltd.Inventors: Dug-Young Kim, Yong-Woo Park, Un-Chul Paek, Mun-Hyun Do
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Patent number: 6813403Abstract: Brillouin scattering spectrum analysis is used to measure strain, displacement, temperature or other physical quantities at any location along an optical fiber attached to a structure. The fiber can be interrogated with different pulse widths for coarse and fine scans. The fiber can also have multiple sensors, either formed in a single fiber or branching off from a backbone fiber, in which case other segments of the fiber can be used for temperature compensation.Type: GrantFiled: May 17, 2002Date of Patent: November 2, 2004Assignee: Fiber Optic Systems Technology, Inc.Inventor: Roderick C. Tennyson
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Patent number: 6807324Abstract: A method and apparatus for calibrating a Distributed Temperature Sensing (DTS) system. One or more discrete temperature sensors are positioned adjacent to a DTS fiber to calibrate data generated from DTS fiber. The discrete temperature sensors preferably comprise FBG (Fiber Bragg Grating) sensors.Type: GrantFiled: May 21, 2002Date of Patent: October 19, 2004Assignee: Weatherford/Lamb, Inc.Inventor: Phillip E. Pruett
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Patent number: 6807325Abstract: The Bragg grating device for measuring an acceleration, has at least two optical Bragg gratings (11, 12), each formed in elastic material, for supplying optical radiation (S) and at least one deflectable mass (M) connected to both gratings for generating an inertial force that is dependent on the acceleration which acts upon the device, in order to produce elastic extension of one of the two gratings and simultaneous elastic contraction of the other grating. The device is also suitable for vibration frequency measurement.Type: GrantFiled: November 20, 2001Date of Patent: October 19, 2004Assignee: Siemens AktiengesellschaftInventors: Peter Kraemmer, Michael Willsch
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Publication number: 20040197050Abstract: Optical device for distributed sensing of a measurand and/or changes thereof where the spectral transmission and reflection characteristics of the device depend upon the measurand. A passive sensing section have at least one Bragg grating sensing structure in a waveguide. The Bragg grating sensing structure comprises at least two superimposed or partly overlapping Bragg subgratings with at least two different Bragg wavelengths. At least two of the said Bragg subgratings comprise a phase-shift. The Bragg subgratings have their phase shifts spatially separated from each other along the waveguide sensing section. The sensing section can be made active by at least partly doping it with rare earth ions and forming a laser medium, or an active component. Examples of using the passive as well as the active sensing sections in optical distributed sensors are described.Type: ApplicationFiled: May 17, 2004Publication date: October 7, 2004Inventors: Sigurd Weidemann Lovseth, Jon Thomas Kringlebotn
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Patent number: 6801676Abstract: An apparatus and method for modulating a phase of optical beam with reduced contact loss. In one embodiment, an apparatus according to embodiments of the present invention includes a first region of an optical waveguide disposed in semiconductor material. The first region has a first conductivity type. The apparatus further includes a second region of the optical waveguide disposed in the semiconductor material. The second region has a second conductivity type, which is opposite to the first conductivity type. A first contact is coupled to the optical waveguide at a first location, which is outside an optical path of an optical beam that is to be directed through the optical waveguide. A first buffer of insulating material is disposed along the optical waveguide between the first contact and the optical path of the optical beam. A buffer plug of insulating material disposed in the optical waveguide on a same side as the first location.Type: GrantFiled: June 24, 2003Date of Patent: October 5, 2004Assignee: Intel CorporationInventor: Ansheng Liu
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Patent number: 6798937Abstract: A pressure actuated optical relay containing a transparent mirror housing, located at the intersection of two optical paths. A solid slug is moved within a channel passing through the transparent mirror housing by the action of pressure exerted by an actuation fluid. The solid slug is moved in or out of the transparent mirror housing to select between the optical paths and is wetted by a liquid metal. When the solid slug is within the optical path, an incoming optical signal is reflected from a wetted surface of the slug. The liquid metal forms a surface tension bond between the slug and wettable metal surfaces within the channel to provide a latching mechanism.Type: GrantFiled: April 14, 2003Date of Patent: September 28, 2004Assignee: Agilent Technologies, Inc.Inventor: Marvin Glenn Wong
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Patent number: 6798956Abstract: Networks may include optical cables to transmit data between various devices in the network. Indicators positioned on or within optical cables may be used to identify cables that have been compromised during installation, movement and/or use of the cables. Indicators may reduce a network downtime by decreasing the time needed to identify compromised cables. In some embodiments, indicators may change color and/or emit light to indicate that an optical cable has been compromised.Type: GrantFiled: July 16, 2002Date of Patent: September 28, 2004Assignee: Sun Microsystems, Inc.Inventor: John M. Morrison
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Publication number: 20040179766Abstract: 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.Type: ApplicationFiled: March 23, 2004Publication date: September 16, 2004Inventors: Forrest L. Williams, Allen H. Tanner, David Marceau, Dennis F. Elkins
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Patent number: 6788835Abstract: A fiber optic sensor comprises two independent fibers having Bragg gratings which are coupled to commutating broadband optical sources through splitters and wavelength discriminators. The ratio of detected optical energy in each of two detectors examining the wave intensity returned to a wavelength discriminator coupled with the characteristic of the wavelength discriminator determines the wavelength returned by the grating. In another embodiment, tunable filters are utilized to detect minimum returned wave energy to extract a sensor wavelength Reference to the original grating wavelength indicates the application of either temperature or strain to the grating. In another embodiment, a plurality of Bragg grating sensor elements is coupled to sources and controllers wherein a dimensional change in a fiber having a Bragg grating is detected using a measurement system comprising broad-band sources, optical power splitters, a high-sensitivity wavelength discriminator, optical detectors, and a controller.Type: GrantFiled: April 24, 2003Date of Patent: September 7, 2004Assignee: IFOS, Inc.Inventors: Behzad Moslehi, Richard James Black, Herbert John Shaw, Keiichiro Toyama
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Patent number: 6788851Abstract: An apparatus and method for adjusting the spectral response of a selected channel within an optical waveguide grating includes a grating attached to a support member. An adjusting mechanism applies two bending moments to the grating support member on both sides of the selected channel. The spectral response of the selected channel is adjusted by altering the bending moments.Type: GrantFiled: July 1, 2003Date of Patent: September 7, 2004Assignee: 3M Innovative Properties CompanyInventors: James R. Bylander, Kavita Vemuri, Robert W. Wilson, Johnny P. Bryant
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Patent number: 6788417Abstract: Infrasound signals in the band 0.02 to 4 Hz are sensed in the presence of ambient noise generated chiefly by wind as integrated pressure variations, which induce detectable changes in the optical path length, along optic fibers, typically extending 100 m. to 1000 m. and more, arrayed at arbitrary geometries. Two fibers connected as a Michelson, Mach-Zehnder or equivalent interferometer where (i) one fiber is coupled to atmosphere while (ii) the other is not for being hermetically sealed in a tube, permit common mode rejection of noise from (i) temperature changes and (ii) strain, including ground vibration. Because the optic fiber infrasound sensors are longer than the distance over which wind-induced pressure changes are coherent, the effects of wind noise on the sensing of infrasound is reduced, and signal-to-noise ratio is increased over a wide bandwidth.Type: GrantFiled: April 30, 1999Date of Patent: September 7, 2004Assignee: The Regents of the University of CaliforniaInventors: Mark Zumberge, Jonathan Berger
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Patent number: 6785443Abstract: The present invention is directed to a system and method for tuning an optical fiber Bragg grating by using a circular mechanism which uniformly stretches the fiber along its length while at the same time preserving the minimal size for stretching.Type: GrantFiled: January 30, 2002Date of Patent: August 31, 2004Assignee: Teraxion Inc.Inventors: Alexis Mendez, Mario Pacheco, Steve Montesanto, Gershon Perelman, William Wang, Jason Zweiback
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Patent number: 6785004Abstract: An apparatus and method for interrogating fiber optic sensors non-intrusively sensing fluid flow within a pipe is provided. The apparatus includes a two-beam interferometer which comprises an optical circuit for generating a series of discrete light pulses that are directed at sensors positioned between pairs of low reflectivity fiber Bragg gratings. The successive light pulses are split into first light pulses and second light pulses, and the second light pulses are delayed a known time period relative to the first pulses. The first and second light pulses are combined onto a single optical fiber and directed through the low reflectivity gratings and the sensors positioned between the gratings. Reflected pulses from the series of pulses impinge on a photo receiver and interrogator, wherein the phase shift between the reflected first light pulses from a particular grating and the reflected second light pulses from the preceding grating, for each sensor are determined.Type: GrantFiled: November 29, 2000Date of Patent: August 31, 2004Assignee: Weatherford/Lamb, Inc.Inventors: Alan D. Kersey, Allen R. Davis, Mark R. Fernald, Charles R. Winston, Timothy J. Bailey
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Patent number: 6782150Abstract: An apparatus for non-intrusively sensing fluid flow within a pipe is provided. The apparatus includes a first sensing array for sensing acoustic signals traveling at the speed of sound through fluid flow within the pipe, a second sensing array for sensing local pressure variations traveling with the fluid flow, and a housing attached to the pipe for enclosing the sensing arrays. The first sensing array includes a plurality of first optical pressure sensors and the second sensing array includes a plurality of second optical pressure sensors.Type: GrantFiled: November 29, 2000Date of Patent: August 24, 2004Assignee: Weatherford/Lamb, Inc.Inventors: Allen R. Davis, Daniel L. Gysling, Charles R. Winston, John M. Faustino, Rebecca S. McGuinn
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Publication number: 20040161197Abstract: An adjustable chromatic dispersion compensator is provided, with the possibility of passive athermalisation. The device includes an optical fiber grating which is fixed on its length to an elongated beam member that has a flexible cantilever portion so that a non-uniform tensile strain induced in the grating reconfigures the group delay response. The chirp of the grating is changed by the bending of the bar, allowing adjustable chromatic dispersion compensation. Adjustment of the central filter wavelength without affecting the grating integrity is further provided. A multi-material construction allows the package to passively compensate for the natural temperature dependence of the filter resonance wavelength by varying the strain in the fiber in response to changes in the ambient temperature.Type: ApplicationFiled: February 4, 2004Publication date: August 19, 2004Applicant: Teraxion Inc.Inventors: Francois Pelletier, Andre Vo Van
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Patent number: 6778717Abstract: A method and apparatus for monitoring a structure and for locating the position of an event including a light source, a waveguide, and a detector means. The waveguide receives light from the light source so that the light is caused to propagate in counter-propagating optical signals in the waveguide. The waveguide includes the counter-propagating optical signals or some characteristic of the signals modified or effected by an external parameter caused by or indicative of the event to provide modified counter-propagating optical signals. The detector means detects the modified counter-propagating optical signals effected by the parameter and determines the time delay or difference between the modified counter-propagating optical signals in order to determine the location of the event.Type: GrantFiled: April 29, 2003Date of Patent: August 17, 2004Assignee: Future Fibre Technologies Pty Ltd.Inventors: Edward E. Tapanes, Jason R Goode, Jim Katsifolis
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Patent number: 6778715Abstract: An optical fiber-based device exhibiting tunable birefringence utilizes a section of fiber including an optically nonlinear core region (i.e., doped with a material such as vanadium or erbium), where the fiber is configured to exhibit circular asymmetry and thus introduce birefringence into the fiber. The circular asymmetry may be accomplished by depositing the nonlinear core material in an asymmetric pattern or by launching the pump signal into an asymmetric mode of the fiber waveguide (i.e., an LP[1,m] mode). Polarization control can be generated by such a device through controlling the intensity of an input optical pump signal, since the pump signal intensity has been found to control the birefringence of a circularly asymmetric fiber waveguide.Type: GrantFiled: November 6, 2002Date of Patent: August 17, 2004Assignee: Fitel U.S.A. Corp.Inventor: Siddharth Ramachandran
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Patent number: 6774354Abstract: The present invention relates to a fiber optic sensing device having utility as a roll sensor and/or a pitch sensor. The sensing device comprises at least one optical fiber supported in a structure, a movable mass supported within the structure, and at least one detector for detecting changes in tension in the at least one optical fiber due to movement of the movable mass. In the sensor of the present invention, the optical fiber(s) are the only deformable structures, thus maximizing sensitivity.Type: GrantFiled: October 15, 2001Date of Patent: August 10, 2004Assignee: The United States of America as represented by the Secretary of the NavyInventor: Gregory H. Ames
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Publication number: 20040151418Abstract: The present invention is directed to a fiber optic media thickness sensor used in a print media or document processing device. The invention is further directed to a method for measuring media thickness in a media processing device using a fiber optic sensor.Type: ApplicationFiled: February 4, 2003Publication date: August 5, 2004Inventors: Jeffrey D. Hall, Tim M. Hoberock
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Publication number: 20040146254Abstract: Networks may include optical cables to transmit data between various devices in the network. Indicators positioned on or within optical cables may be used to identify cables that have been compromised during installation, movement and/or use of the cables. Indicators may reduce a network downtime by decreasing the time needed to identify compromised cables. In some embodiments, indicators may change color and/or emit light to indicate that an optical cable has been compromised.Type: ApplicationFiled: July 16, 2002Publication date: July 29, 2004Inventor: John M. Morrison
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Patent number: 6768825Abstract: A method and device for pressure sensing using an optical fiber having a core, a cladding and a Bragg grating imparted in the core for at least partially reflecting an optical signal at a characteristic wavelength. The cladding has two variation regions located on opposite sides of the Bragg grating to allow attachment mechanisms to be disposed against the optical fiber. The attachment mechanisms are mounted to a pressure sensitive structure so as to allow the characteristic wavelength to change according to pressure in an environment. In particular, the variation region has a diameter different from the cladding diameter, and the attachment mechanism comprises a ferrule including a front portion having a profile substantially corresponding to at least a portion of the diameter of the variation region and a butting mechanism which holds the ferrule against the optical fiber.Type: GrantFiled: June 1, 2001Date of Patent: July 27, 2004Assignee: Weatherford/Lamb, Inc.Inventors: Robert J. Maron, Guy A. Daigle, James R. Dunphy, Thomas W. Engel, John J. Grunbeck, Mark R. Fernald
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Patent number: 6763160Abstract: A method and apparatus are disclosed for an optical fiber cross-connect switch incorporating an absolute position encoder and a magnetic actuation system into its alignment system. The switch comprises two optically opposed arrays of fiber-optic switching units, each of which contains a single fiber active to send or receive an optical communication signal. The magnetic actuation system comprising four magnetically polarizable actuator branches positioned surrounding the fiber and a magnetizable disk circumferentially attached to the fiber end. Selective magnetic polarization of the actuator branches bends the fiber end. A two-dimensional Moiré type position encoder determines the absolute position of the fiber end. The encoder comprises at east one plurality of radiation sources, which emits pulses of radiation (control signals) directed toward the switching units.Type: GrantFiled: April 26, 2001Date of Patent: July 13, 2004Assignee: Creo SRLInventors: Michel Laberge, Thomas W. Steiner, Valentin Karasyuk
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Patent number: 6763154Abstract: 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 electrostatical force, mechanical force, or tiltable flaps.Type: GrantFiled: May 20, 2002Date of Patent: July 13, 2004Assignee: JDS Uniphase Inc.Inventors: Robert I. MacDonald, Barrie Keyworth, Alan J. P. Hnatiw
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Patent number: 6756580Abstract: Fiber grating environmental measurement systems are comprised of sensors that are configured to respond to changes in moisture or chemical content of the surrounding medium through the action of coatings and plates inducing strain that is measured. These sensors can also be used to monitor the interior of bonds for degradation due to aging, cracking, or chemical attack. Means to multiplex these sensors at high speed and with high sensitivity can be accomplished by using spectral filters placed to correspond to each fiber grating environmental sensor. By forming networks of spectral elements and using wavelength division multiplexing arrays of fiber grating sensors may be processed in a single fiber line allowing distributed high sensitivity, high bandwidth fiber optic grating environmental sensor systems to be realized.Type: GrantFiled: June 10, 2003Date of Patent: June 29, 2004Inventors: Whitten Lee Schulz, Eric Udd
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Patent number: 6753520Abstract: Fiber optic sensor with transmission/reflection analyzer for detection and localization of a perturbation that generates additional losses in the test fiber.Type: GrantFiled: September 17, 2001Date of Patent: June 22, 2004Assignees: Centro de Investigacion Cientifica y de Educacion Superior de Ensenada (CICESE), Centro de Investigacion en Materiales Avanzados, S.C.Inventors: Vasilii V. Spirin, Mikhail G. Shlyagin, Serguei V. Miridonov, Francisco J. Mendieta Jiménez, Alfredo Márquez Lucero
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Publication number: 20040114850Abstract: According to the invention, that relates particularly to monitoring of structures, part of the optical fiber (4) containing a Bragg grating (R) is arranged in a tube (16); this part is tensioned between the two ends of the tube; the ends of this part are fixed to the ends of the tube; this tube will be rigidly fixed to a host material (2).Type: ApplicationFiled: October 3, 2003Publication date: June 17, 2004Inventors: Veronique Dewyntermarty, Stephane Rougeault, Pierre Ferdinand
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Publication number: 20040114849Abstract: A multiple mode pre-loadable fiber optic pressure and temperature sensor includes a generally cylindrical structure having at least one compression element, a fiber optic having a Bragg grating in contact with one side of the compression element, a diaphragm in contact with the other side of the compression element, and a fluid port in fluid communication with the diaphragm. According to preferred aspects of the, a groove is provided in at least one compression element for receiving the fiber optic. The sensor is pre-loaded by straining the diaphragm over the adjacent compression element when the cover is attached. The compression element in contact with the diaphragm preferably has a contoured surface contacting the diaphragm and the diaphragm is stretched to match that contour. By varying the contour of the compression element and the thickness of the diaphragm, the dynamic range of the sensor can be changed. The preferred diaphragm has a variable thickness and is made as an integral part of the structure.Type: ApplicationFiled: December 16, 2002Publication date: June 17, 2004Applicant: SCHLUMBERGER TECHNOLOGY CORPORATIONInventors: Jagdish Shah, Robert Schroeder, Philip Dryden, Rogerio Ramos, Raghu Madhavan
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Patent number: 6751367Abstract: A fiber optic sensor comprises two independent fibers having Bragg gratings which are coupled to commutating broadband optical sources through splitters and wavelength discriminators. The ratio of detected optical energy in each of two detectors examining the wave intensity returned to a wavelength discriminator coupled with the characteristic of the wavelength discriminator determines the wavelength returned by the grating. In another embodiment, tunable filters are utilized to detect minimum returned wave energy to extract a sensor wavelength Reference to the original grating wavelength indicates the application of either temperature or strain to the grating. In another embodiment, a plurality of Bragg grating sensor elements is coupled to sources and controllers wherein a dimensional change in a fiber having a Bragg grating is detected using a measurement system comprising broad-band sources, optical power splitters, a high-sensitivity wavelength discriminator, optical detectors, and a controller.Type: GrantFiled: April 24, 2003Date of Patent: June 15, 2004Assignee: IFOS, Inc.Inventors: Behzad Moslehi, Vahid Sotoudeh, Brian Kutner, Dario G. Falquier, Levy Oblea
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Publication number: 20040109642Abstract: The invention relates to a method and an apparatus for manufacturing an optical coupling arrangement, and a specific coupling arrangement. A substrate waveguide (306) and at least one coupling element (304, 306) in the coupling arrangement are made of polymer material in the same replication process at the same time. At least one diffractive coupling element (304, 306) is then formed in the polymer material by placing the polymer material against a replication mould, which comprises a surface profile model of at least one diffractive coupling element (304, 306) that is patterned into the replication mould by means of micro lithography.Type: ApplicationFiled: October 14, 2003Publication date: June 10, 2004Inventors: Marko Parikka, Jari Turunen
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Patent number: 6740866Abstract: The subject matter of the present invention is a fiber Bragg grating sensor 1, 25 which is suitable, in particular, for measuring differential pressures and flow rates v1 in oil drill holes. The sensor principle according to the invention is based on using a transducer 1 with two pressure chambers 7a, 7b to convert a hydrostatic pressure difference between two liquid or gaseous media 11a, 11b into a longitudinal fiber elongation or fiber compression and measuring it via the displacement of the Bragg wavelength &Dgr;&lgr;B of at least one fiber Bragg grating 3, 4. Exemplary embodiments are specified which have two fiber Bragg gratings 3, 4 which are sensitive to elongation in opposite senses and which have temperature-compensating transducers 1, and which have a plurality of transducers 1 in a wavelength-division-multiplexing configuration. One embodiment relates to measuring a flow rate v1 with the aid of a venturi tube 23.Type: GrantFiled: June 15, 2001Date of Patent: May 25, 2004Assignee: ABB Research LtdInventors: Klaus Bohnert, Hubert Brändle