公开(公告)号：JPH10185585A

公开(公告)日：1998-07-14

申请号：JP31826297

申请日：1997-11-19

Applicant: LITTON SYSTEMS INC

Inventor： CORDOVA AMADO ,  HOOVER ROBERT J ,  MCLEAN THOMAS ,  PATTERSON RALPH A ,  RAHN JOHN P

IPC: G01C19/72 ,  G02B6/44

Abstract: PROBLEM TO BE SOLVED: To reduce gyro errors by releasing the stress between windings, by providing a means which reduces the thermal stress between a jacket and a burying material. SOLUTION: A surface 26 of the external jacket of the sensor coil composed of an optical fiber 28 is insulated from a surrounding burying material 30 by lubricant layers 32 and 34, which surround the wound layer of a fiber 29. Before starting the winding process of the sensor coil, the lubricant layer applying process, and the burying process of the sensor coil, the burying material 30 is applied to the surface of a supporting mandrel. After the material 30 is applied, the lubricant layer 34 is applied to the surface of the burying material 30 with a brush or spray and the layer of the fiber 28 is wound. After the fiber 28 is wound, the lubricant layer 32 is applied to the surface of the fiber 28 with a spray or brush, and the remaining layer of the burying material 36 is applied. Since the lubricant layers 34 and 32 are respectively provided immediately below and above the fiber 28, the fiber 28 is isolated from the layers 30 and 36 of the burying material 30 by the lubricants.

公开(公告)号：JPH11145534A

公开(公告)日：1999-05-28

申请号：JP30160697

申请日：1997-11-04

Applicant: LITTON SYSTEMS INC

Inventor： JAMES ROSS STEELE ,  GOLDNER ERIC LEE ,  RONALD JAMES MICHAEL ,  FIDRIC BERNARD G ,  PATTERSON RALPH A

IPC: G01C19/72 ,  G02B6/00 ,  H01S3/06 ,  H01S3/067 ,  H01S3/083 ,  H01S3/0933 ,  H01S3/23 ,  H01S5/068 ,  H01S5/0683

Abstract: PROBLEM TO BE SOLVED: To obtain a fiber laser of superfluorescent wideband by a method, wherein an optical output of an edge-emission type light-emitting diode is amplified by an optical fiber amplifier and used as a light source for a fiber gyro. SOLUTION: An electric source 11 serving as a power supply supplies power to an optical amplifier 12 and a current source 13. The current source 13 sends a drive current or a bias current to the input port 20 of the light amplifier 12 from a wideband light source such as an emission-type light-emitting diode 15, so as to control the intensity of output light signals. The emission-type light-emitting diode 15 is actuated by a bias current of 50 to 80 Ma to generate an average power of 30 to 60 Uw in terms of power spectrum density, having a smooth wideband distribution. The optical amplifier 12 which is used to amplify output light signals 14 is used in combination to enable its output port 18 to output sufficient power. The gain of an optical amplifier is nearly flat on a problematic bandwidth, and a light signal 16 which is power-boosted can be outputted from the output port 18.

公开(公告)号：WO9603620A3

公开(公告)日：1996-05-30

申请号：PCT/US9509427

申请日：1995-07-26

Applicant: LITTON SYSTEMS INC

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

IPC: G01C19/72 ,  G01R33/032

CPC classification number: G01C19/721

Abstract: A fiber optic sensing coil formed in a polarization-maintaining optical fiber has two optical fiber leads extending therefrom. A multifunction integrated optics chip linearly polarizes optical signals input to the sensing coil. Fiber optic leads formed of polarization-maintaining optical fiber extend from the multifunction integrated optics chip. The fiber optic multifunction integrated optics chip leads are arranged such that the linear polarization of optical signals output from the multifunction integrated optics chip is directed along one of the principal axes of birefringence of each of the fiber optic multifunction integrated optics chip leads. Splices are formed between corresponding the first sensing coil leads and the multifunction integrated optics chip leads. The sensing coil leads and the multifunction integrated optics chip leads are arranged such that their corresponding principal axes of birefringence are at angles of approximately 45° relative to one another. The first splice is formed a distance from the multifunction integrated optics chip such that a selected phase change between polarization components occurs in optical waves that propagate the distance L1 in the first multifunction integrated optics chip lead.

公开(公告)号：CA2117635A1

公开(公告)日：1995-03-04

申请号：CA2117635

申请日：1994-09-02

Applicant: LITTON SYSTEMS INC

Inventor： PATTERSON RALPH A

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

Abstract: A rotation sensor for use in a fiber optic gyroscope includes a substantially-planar disk-like coil mounting member of titanium. A wound sensor coil is supported by the member in an edgewise fashion, allowing free expansion of the sensor coil in the direction orthogonal to the plane of the member to minimize thermally-induced stressing of the sensor coil. In an alternative embodiment, the free-standing coil is effectively "split"; that is, one-half is mounted to one side of the member and the remainder to the other side in such a way that the sensitive axes are coincident. Edge ramps are provided in the member for guiding the continuous optical fiber comprising the coil segments from one side of the disk-like mounting member to the other without microbends. A cylindrical inner hub includes a thinned and flexible portion for contacting a mounting pedestal of stainless steel composition whereby the differential thermal expansions of the pedestal and mounting member materials will not produce misalignment of the sensor coil with respect to a predetermined input axis of rotation.

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：DE69406185D1

公开(公告)日：1997-11-20

申请号：DE69406185

申请日：1994-04-06

Applicant: LITTON SYSTEMS INC

Inventor： PATTERSON RALPH A ,  WILDE JOHN D

IPC: G01C19/72 ,  G02B6/00

公开(公告)号：CA2219592A1

公开(公告)日：1999-04-29

申请号：CA2219592

申请日：1997-10-29

Applicant: LITTON SYSTEMS INC

Inventor： PATTERSON RALPH A ,  GOLDNER ERIC LEE ,  STEELE JAMES ROSS ,  FIDRIC BERNARD G ,  MICHAL RONALD JAMES

IPC: G01C19/72 ,  G02B6/00 ,  H01S3/06 ,  H01S3/067 ,  H01S3/083 ,  H01S3/0933 ,  H01S3/23 ,  H01S5/068 ,  H01S5/0683 ,  H04B10/16

Abstract: A power boosted source of broadband optical power comprising a broadband light source, optical fiber amplifier and a relative intensity noise reduction system. The optical fiber amplifier amplifies the power level of the optical input signal to provide a power boosted source of broadband optical power out of an output port. A coupler samples a portion of the broadband optical power out of the output port as a sample portion signal. A detector and transimpedance amplifier detect the optical signal and provide a buffered signal having an instantaneous amplitude that faithfully characterizes the intensity of the sample portion signal. A bandpass amplifier amplifies the buffered signal and provides an output control signal to a light source responsive to a composite bias and control current for providing an output optical signal. The output optical signal is coupled to the input of the optical fiber amplifier to be the optical input signal to the optical fiber amplifier. The output optical signal from the ELED has a substantially constant output intensity level and smooth and bell shaped broad band spectrum with a center optical wavelength within the gain bandwidth of the optical fiber amplifier.

公开(公告)号：CA2237205A1

公开(公告)日：1999-01-28

申请号：CA2237205

申请日：1998-05-08

Applicant: LITTON SYSTEMS INC

Inventor： PATTERSON RALPH A ,  RAHN JOHN P

IPC: G01C19/72 ,  G01C25/00 ,  G01M11/02 ,  G01M11/08

Abstract: The invention is a method and apparatus for quantitatively characterizing the pr essure induced nonreciprocity of a fiber-optic coil where the pressure-induced nonreciprocity i s a property of a fiber-optic coil which pertains to the degree to which light beams , initially in phase, differ in phase as a result of traversing the fiber-optic coil in reverse direct ions while the fiber-optic coil is being subjected to a time-varying pressure. The method compr ises the steps of applying time-varying pressure to the fiber-optic coil for a predetermined time period, measuring the phase difference of light beams traversing the fiber-optic coil in reverse d irections during the predetermined time period, and obtaining a measure of the nonreciprocity of the fiber-optic coil utilizing the measured phase difference. If the time-varying pressure is specifi ed by a first function of time, the measure of the nonreciprocity is the integral over the pre determined time period of the product of a second function of time and either (1) the phase diff erence of light beams traversing the fiber-optic coil in reverse directions during the predeterm ined time period or (2) the integral over time of the phase difference. The second function is ch osen such that the measure of the nonreciprocity has a signal-to-noise ratio of at least one. Prefe rably, the second function is (1) an approximation of the time derivative of the first function if the product involves the phase difference or (2) an approximation of the first function if t he product involves the integral of the phase difference. The invention also includes the apparatus for practicing the method.

公开(公告)号：CA2122275A1

公开(公告)日：1994-11-11

申请号：CA2122275

申请日：1994-04-27

Applicant: LITTON SYSTEMS INC

Inventor： PATTERSON RALPH A ,  WILDE JOHN D

IPC: G01C19/72 ,  G02B6/00

Abstract: A method for tuning a sensor coil for a fiber optic gyroscope. The coil is initially wound in a known pattern. One end of the fiber of the wound coil is then adjusted relative to the other end so that a known differential is obtained that effectively displaces the midpoint of the winding pattern. The coil is then attached to an interferometer test apparatus and performance measured. After successive observations a "trimmed" coil is obtained of acceptable performance characteristics.

公开(公告)号：DE69409686D1

公开(公告)日：1998-05-28

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.