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公开(公告)号：AT59468T
公开(公告)日：1991-01-15
申请号：AT85302571
申请日：1985-04-12
Applicant: LITTON SYSTEMS INC
Inventor： PAVLATH GEORGE A
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公开(公告)号：DE4000800A1
公开(公告)日：1990-08-09
申请号：DE4000800
申请日：1990-01-12
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：CA2003945A1
公开(公告)日：1990-08-03
申请号：CA2003945
申请日：1989-11-27
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：GB2223860A
公开(公告)日：1990-04-18
申请号：GB8916655
申请日：1989-07-21
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：DE3566045D1
公开(公告)日：1988-12-08
申请号：DE3566045
申请日：1985-03-07
Applicant: LITTON SYSTEMS INC
Inventor： PAVLATH GEORGE A
Abstract: This invention relates to fiber optic apparatus and methods for polarizing light for use in fiber optic devices, such as rotation sensors. A phase grating (52) formed of alternating layers of dielectrics (54,56) having different indices of refraction is placed adjacent a half coupler (12) that includes a fiber (20,22) having a cladding thickness which forms an interaction region. The evanescent field of light of a selected polarization interacts with the phase grating (52) to couple out of the fiber (20,22) while light of a second selected polarization remains in the fiber (20,22).
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Patent Agency Ranking
公开(公告)号：AT38567T
公开(公告)日：1988-11-15
申请号：AT84308380
申请日：1984-12-03
Applicant: LITTON SYSTEMS INC
Inventor： PAVLATH GEORGE A
IPC: G02B5/30 , G02B6/00 , G02B6/024 , G02B6/10 , G02B6/14 , G02B6/26 , G02B6/28 , G02B6/34 , G02B27/28 , G02F1/01
Abstract: This invention provides apparatus and methods for converting a lightwave of an arbitrary polarization propagating in a single mode optical fiber into a wave having a single linear polarization state. A polarization couples light of an undesired polarization out of the fiber, and a photodetector produces an error signal responsive to light coupled from the fiber. Control circuitry processes the error signal to produce control signals which are input to a polarization of light input to the polarizer to null the error signal. With the error signal maintained at a minimum value the light input to the polarizer and, hence, the light output therefrom is a wave having only the desired linear polarization.
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公开(公告)号：AU568798B2
公开(公告)日：1988-01-07
申请号：AU7136387
申请日：1987-04-09
Applicant: LITTON SYSTEMS INC
Inventor： PAVLATH GEORGE A
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公开(公告)号：AU559506B2
公开(公告)日：1987-03-12
申请号：AU4575885
申请日：1985-08-05
Applicant: LITTON SYSTEMS INC
Inventor： PAVLATH GEORGE A
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公开(公告)号：AU557221B2
公开(公告)日：1986-12-11
申请号：AU3988885
申请日：1985-03-15
Applicant: LITTON SYSTEMS INC
Inventor： PAVLATH GEORGE A
Abstract: This invention relates to fiber optic apparatus and methods for polarizing light for use in fiber optic devices, such as rotation sensors. A phase grating (52) formed of alternating layers of dielectrics (54,56) having different indices of refraction is placed adjacent a half coupler (12) that includes a fiber (20,22) having a cladding thickness which forms an interaction region. The evanescent field of light of a selected polarization interacts with the phase grating (52) to couple out of the fiber (20,22) while light of a second selected polarization remains in the fiber (20,22).
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公开(公告)号：AU5056085A
公开(公告)日：1986-11-13
申请号：AU5056085
申请日：1985-12-02
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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