公开(公告)号：AU5022885A

公开(公告)日：1986-10-09

申请号：AU5022885

申请日：1985-11-21

Applicant: LITTON SYSTEMS INC

Inventor： PAVLATH GEORGE A

IPC: H01S3/083 ,  G01C19/64 ,  G01C19/72 ,  G01P9/00 ,  G02F1/01

Abstract: @ 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.

公开(公告)号：NO855315A

公开(公告)日：1986-10-02

申请号：NO855315

申请日：1985-12-27

Applicant: LITTON SYSTEMS INC

Inventor： PAVLATH GEORGE A

IPC: H01S3/083 ,  G01C19/64 ,  G01C19/72 ,  G01P9/00 ,  G02F1/01 ,  G01C

CPC classification number: G01C19/726

公开(公告)号：NO853297L

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

IPC: G02B5/30 ,  G02B6/024 ,  G02B6/10 ,  G02B6/28 ,  G02B

公开(公告)号：BR8503103A

公开(公告)日：1986-05-27

申请号：BR8503103

申请日：1985-06-27

Applicant: LITTON SYSTEMS INC

Inventor： PAVLATH GEORGE A

IPC: G02B6/24 ,  G02B6/26 ,  G02B6/28 ,  G02B6/35 ,  G02B6/36 ,  G02B6/38 ,  G02F1/313

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.

公开(公告)号：NO852237L

公开(公告)日：1985-12-12

申请号：NO852237

申请日：1985-06-03

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 ,  G02B

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.

公开(公告)号：BR8405444A

公开(公告)日：1985-09-03

申请号：BR8405444

申请日：1984-10-25

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 ,  H01S3/10

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.

公开(公告)号：NO844693L

公开(公告)日：1985-06-06

申请号：NO844693

申请日：1984-11-26

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 ,  G02B

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.

公开(公告)号：DE69409686T2

公开(公告)日：1998-08-13

申请号：DE69409686

申请日：1994-01-19

Applicant: LITTON SYSTEMS INC

Inventor： HUANG SIDNEY XI-YI ,  MICHAL RONALD J ,  PATTERSON RALPH A ,  PAVLATH GEORGE A

IPC: G01C19/72 ,  G02B6/00 ,  G02B6/44

Abstract: The compensated sensor coil includes arrangements formed at two leads of the sensor coil for compensating the bias shifts. One of such arrangements comprises at least one loop of optical fibre for compensating the effect induced by the magnetic field component oriented transverse to the axis of the sensor coil while the other comprises at least one loop oriented at a predetermined pitch angle for compensating the effect induced by a magnetic field component along the axis. The sensor coil is characterised by a number of randomly distributed fibre twist modes. In each case, a predetermined degree of twist of a preselected fibre twist mode is imposed upon the compensator loop for creating a counteracting, corrective Faraday effect The twist rate of a predetermined twist mode of the turn of the compensator is selected to offset the Faraday effect due to an applied magnetic field having a known orientation with respect to the axis of the sensor coil. The twist rate of the predetermined twist mode of the compensator is a function of the twist rate of the corresponding twist mode of the sensor coil.

公开(公告)号：DE3580196D1

公开(公告)日：1990-11-29

申请号：DE3580196

申请日：1985-04-15

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

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.

公开(公告)号：AT57765T

公开(公告)日：1990-11-15

申请号：AT85302622

申请日：1985-04-15

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

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.