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公开(公告)号：CA2014958A1
公开(公告)日：1991-10-19
申请号：CA2014958
申请日：1990-04-19
Applicant: LITTON SYSTEMS INC
Inventor： PAVLATH GEORGE A
IPC: G02B6/24
Abstract: METHODS FOR RUGGED ATTACHMENT OF FIBERS TO INTEGRATED OPTICS CHIPS AND PRODUCT THEREOF Methods are disclosed for providing a rugged attachment of an optical fiber to an integrated optics chip. A first plate is attached to a first surface of the chip, the thickness of the chip is reduced to a value less than the diameter of the fiber but of sufficient optical thickness so that the evanescent field of a guided mode is negligible outside the chip, a second plate is attached to a second major surface of the reduced-thickness chip, the fiber is coaxially jacketed with a material suitable for attachment to the first and second plates, the fiber is positioned with respect to a waveguide on the chip, and the jacket of the fiber at its end face is symmetrically attached to both the first and second plates at a plurality of locations. Alternatively, a single plate can be attached to the first surface of the chip without reducing the thickness of the chip and either a jacket on the fiber or the curved periphery of the fiber itself can be attached symmetrically to both the plate and the substrate. The resulting connection between the optical fiber and the integrated optics chip is rugged, thermally insensitive, and suited for batch production processes. A wafer comprising a plurality of chips can be sandwiched between first and second plates or reinforced with a single plate, and subsequently subdivided into individual chips to which optical fibers can then be attached.
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公开(公告)号：DE3581032D1
公开(公告)日：1991-02-07
申请号：DE3581032
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：FR2642843A1
公开(公告)日：1990-08-10
申请号：FR9000805
申请日：1990-01-24
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：CA1262179A
公开(公告)日：1989-10-03
申请号：CA499335
申请日：1986-01-10
Applicant: LITTON SYSTEMS INC
Inventor： PAVLATH GEORGE A
Abstract: CLOSED LOOP ALL FIBER OPTIC GYROSCOPE WITH DIFFERENTIAL FREQUENCY PROPAGATION A gyroscope system includes a coherent light source that supplies counterpropagating waves to a sensing loop through a pair of directional couplers. The polarizations of the waves are controlled so that they traverse identical paths before recombining in one of the couplers to form an interference pattern. Rotation of the sensing loop, a phase modulator and a frequency shifter cause phase changes in the counter propagating waves. A detector monitors the interference pattern of the combined waves and provides a signal to the coherent demodulator that controls the phase modulator. The output of the coherent demodulator is input to a servo loop circuit that drives a voltage controlled oscillator. The output of the voltage controlled oscillator is an oscillatory signal having a frequency equal to the shift in frequency that the counter propagating waves experience in traversing the frequency shifter. The feedback circuitry adjusts the frequency shift to null the phase difference between the counterpropagating waves. The frequency shift is linearly related to the frequency of the signal output from the voltage controlled oscillator. Each cycle of the output of the voltage controlled oscillator corresponds to a fixed angular increment of displacement of the sensing loop. The rotation rate of the sensing loop is a function of the frequency shift and transit time of the waves through the sensing loop. The gyroscope system determines rotation rates and angular displacements over a wide dynamic range by measuring the frequency and zero crossings of the oscillatory output of the voltage controlled oscillator.
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公开(公告)号：CA1249155A
公开(公告)日：1989-01-24
申请号：CA464609
申请日：1984-10-03
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: FIBER OPTIC POLARIZER WITH ERROR SIGNAL FEEDBACK 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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Patent Agency Ranking
公开(公告)号：CA1249028A
公开(公告)日：1989-01-17
申请号：CA496259
申请日：1985-11-26
Applicant: LITTON SYSTEMS INC
Inventor： PAVLATH GEORGE A
Abstract: CHANNELIZED FIBER OPTIC RECEIVER 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：AT38438T
公开(公告)日：1988-11-15
申请号：AT85301558
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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公开(公告)号：AU558057B2
公开(公告)日：1987-01-15
申请号：AU3988785
申请日：1985-03-15
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 , G02F1/01 , G02F1/21 , G08C15/06 , G08C23/00
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：NO855361A
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
CPC classification number: G02B6/2861
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公开(公告)号：AU3988785A
公开(公告)日：1985-12-19
申请号：AU3988785
申请日：1985-03-15
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 , G02F1/01 , G02F1/21 , G08C15/06 , G08C23/00
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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