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公开(公告)号：CA1295828C
公开(公告)日：1992-02-18
申请号：CA576344
申请日：1988-09-01
Applicant: LITTON SYSTEMS INC
Inventor： PAVLATH GEORGE A
Abstract: FIBER OPTIC GYROSCOPE WITH IMPROVED BIAS STABILITY AND REPEATABILITY AND METHOD OF THE DiSCLOSURE A fiber gyroscope provides improved bias stability and repeatability and has a greatly reduced polarizer extinction ratio requirement compared previous devices. This fabrication technique is compatible with both an all fiber gyroscope configuration and an integrated optics or bulk optics device. The present invention comprises a substrate that is preferably formed of fused silica. A pair of optical fibers, or two lengths of one fiber, are mounted to the substrate, and first planar surfaces are formed in the cladding. Optical couplers, polarizers and other components used in forming the rotation sensor are formed on the planar cladding surfaces of the fibers. Polarizers formed on the fibers have a transmission axis aligned with an axis of birefringence of the fiber to remove undesired linear polarization components from optical signals guided by the fibers while permitting a desired linear polarization component to propagate unattenuated. A sensing coil of optical fiber is arranged to guide light between the first and second optical fibers, the first and second optical fibers and the optical coupler cooperating to introduce counterpropagating light waves in the sensing coil.
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公开(公告)号：AT59710T
公开(公告)日：1991-01-15
申请号：AT85305071
申请日：1985-07-17
Applicant: LITTON SYSTEMS INC
Inventor： PAVLATH GEORGE A
Abstract: This invention relates to an electrically switchable fiber optic directional coupler. Two oppositely oriented blocks of an interaction material are placed adjacent the fibers in an evanescent field coupler. Application of an electromagnetic field to the interaction material increases the refractive index of one fiber and decreases the refractive index of the other. The change in refractive indices of the blocks of the interaction material increases the propagation constant of one fiber and decreases that of the other fiber. The coupling of optical signals between the fibers may be varied between zero and 100% by controlling the aplied field to change the propagation constants between values that provide complete cross coupling of light from one fiber into the other and straight through propagation provides an electrically controllable switching action.
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公开(公告)号：FR2637975A1
公开(公告)日：1990-04-20
申请号：FR8910685
申请日：1989-08-08
Applicant: LITTON SYSTEMS INC
Inventor： PAVLATH GEORGE A
Abstract: Devices and methods for use in integrated optics waveguide circuits containing Y-junctions are presented for intercepting and either absorbing or otherwise removing radiation which has leaked into the substrate in order that such leaked radiation cannot re-enter the waveguide circuit and cause signal errors.
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公开(公告)号：IT9067083D0
公开(公告)日：1990-02-02
申请号：IT6708390
申请日：1990-02-02
Applicant: LITTON SYSTEMS INC
Inventor： PAVLATH GEORGE A
Abstract: A closed loop fiber optic rotation sensing system prevents the occurrence of instabilities in its feedback signal by modulating the counterpropagating waves with a reference signal and demodulating an electrical signal indicative of the phase difference of two counterpropagating waves with the reference signal. The modulating means is driven to null the phase difference between the counterpropagating waves, and the feedback signal is adjusted to prevent instability. The counterpropagating waves may be either phase modulated or shifted in frequency. The means for modulating the counterpropagating waves may comprise a fiber optic frequency shifter connected to the fiber optic sensing coil and means for applying the reference signal to the frequency shifter. The feedback signal is adjusted with either a pseudo-random or a periodic signal having a zero mean value to prevent instability.
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公开(公告)号：AU558060B2
公开(公告)日：1987-01-15
申请号：AU4305185
申请日：1985-05-28
Applicant: LITTON SYSTEMS INC
Inventor： PAVLATH GEORGE A
Abstract: This invention relates to an electrically switchable fiber optic directional coupler. Two oppositely oriented blocks of an interaction material are placed adjacent the fibers in an evanescent field coupler. Application of an electromagnetic field to the interaction material increases the refractive index of one fiber and decreases the refractive index of the other. The change in refractive indices of the blocks of the interaction material increases the propagation constant of one fiber and decreases that of the other fiber. The coupling of optical signals between the fibers may be varied between zero and 100% by controlling the aplied field to change the propagation constants between values that provide complete cross coupling of light from one fiber into the other and straight through propagation provides an electrically controllable switching action.
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Patent Agency Ranking
公开(公告)号：NO855361L
公开(公告)日：1986-11-11
申请号：NO855361
申请日：1985-12-30
Applicant: LITTON SYSTEMS INC
Inventor： PAVLATH GEORGE A
Abstract: A receiver includes apparatus for modulating a signal onto an optical carrier. A plurality of fiber optic filters analyses the modulated carrier. Each of the filters has a unique, predetermined center frequency and bandwidth. The filters are arranged to provide a predetermined continuous receiver frequency range.
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公开(公告)号：NO853297A
公开(公告)日：1986-10-02
申请号：NO853297
申请日：1985-08-21
Applicant: LITTON SYSTEMS INC
Inventor： PAVLATH GEORGE A
CPC classification number: G02B6/105 , G02B6/2821
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公开(公告)号：BR8502049A
公开(公告)日：1986-05-06
申请号：BR8502049
申请日：1985-04-30
Applicant: LITTON SYSTEMS INC
Inventor： PAVLATH GEORGE A
IPC: G01D5/26 , G01D5/353 , G01D21/00 , G01H9/00 , G01J1/02 , G01J9/00 , G01N21/00 , G01R9/00 , G01R33/032 , G02B6/00 , G02B6/28
Abstract: This invention provides a sensor array using a plurality of fiber optic sensors connected between transmit fibers and receive fibers. The laser transmitter supplies pulses to the transmit fiber and fiber optic couplers couple the pulses from the transmit fiber into the fiber optic sensors. The pulses from the laser transmitter may be frequency chirped or frequency stepped to provide passive sampling of interferometric sensors in addition to intensity sensors, or otherwise frequency modulated. Each sensor is configured to respond to changes in a predetermined physical parameter by altering the shape of the pulse thereto. Fiber optic couplers couple the sensor output signals into the receive fiber for input to a receiver, which converts the optical signals into electrical signals for input to a processor. A timing reference correlates the sensor output pulses with the sensors.
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公开(公告)号：AU3988685A
公开(公告)日：1985-11-28
申请号：AU3988685
申请日：1985-03-15
Applicant: LITTON SYSTEMS INC
Inventor： PAVLATH GEORGE A
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公开(公告)号：NO851016L
公开(公告)日：1985-09-17
申请号：NO851016
申请日：1985-03-14
Applicant: LITTON SYSTEMS INC
Inventor： PAVLATH GEORGE A
IPC: G02B20060101 , G02B
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