Patents Represented by Attorney John H. Lynn
  • Patent number: 5777737
    Abstract: A fiber optic rotation sensor includes a 3.times.3 optical coupler formed of first, second and third optical waveguides. The first, second and third optical waveguides are formed such that the fractions of light coupled from any one of the first, second and third optical waveguides to the other two optical waveguides are constant, independent of thermally-induced changes in the interaction length. An optical signal source provides an input optical signal to the first optical waveguide such that portions of the input optical signal are coupled from the first optical waveguide into the second and third optical waveguides. The optical fiber in which the sensing loop is formed has ends that are coupled to the second and third optical waveguides to receive optical signals that form counterpropagating optical waves in a fiber optic sensing loop and to combine the counterpropagating optical waves after they have traversed the sensing loop.
    Type: Grant
    Filed: February 5, 1997
    Date of Patent: July 7, 1998
    Assignee: Litton Systems, Inc.
    Inventor: John F. Priest
  • Patent number: 5513039
    Abstract: A mirror for reflecting a selected frequency of light includes a plurality of alternating quarter wavelength thick layers of two dielectric materials that are resistive to physical and chemical changes upon exposure to ultraviolet radiation coated upon a substrate. The materials have different refractive indices. The materials preferably are comprised of a mixture of alumina and tantala as the high refractive index layer and alumina as the low refractive index layer.
    Type: Grant
    Filed: May 26, 1993
    Date of Patent: April 30, 1996
    Assignee: Litton Systems, Inc.
    Inventors: Samuel Lu, Ming-Jau Sun, Alan F. Stewart, Anthony W. Louderback
  • Patent number: 5504720
    Abstract: A plurality of air-backed elongate mandrels are arranged in an planar array such that their longitudinal axes are parallel. A length of a first optical fiber is wound around portions of each mandrel in a first group of the mandrels for exposure to the parameter. The first optical fiber is arranged such that exposing it to the parameter to be sensed causes the length of the first optical fiber to increase and decrease in direct proportion as the parameter increases and decreases. A length of the second optical fiber is wound around a second group of the mandrels for exposure to the parameter. The second optical fiber preferably is arranged such that exposing it to the parameter to be sensed causes the length of the second optical fiber to increase and decrease in inverse proportion as the parameter increases and decreases.
    Type: Grant
    Filed: March 20, 1995
    Date of Patent: April 2, 1996
    Assignee: Litton Systems, Inc.
    Inventors: A. Douglas Meyer, Bruce Danver, Emery Moore
  • Patent number: 4807170
    Abstract: A drug dosage calculation system includes a hand held, battery operated computing device for use by nurses and other clinical personnel to make calculations pertaining to the drug administration rate and the corresponding flow rate settings of IV systems that are used for intravenous administration of fluids to a patient. Flow rate setting, drug dose rate, drug amount and the amount of IV solution into which the drug is diluted are the primary variables used in such calculations. A keyboard is used to supply data to a computation device that computes the unknown quantity. A display device displays the data input to the computer and also displays data calculated for the unknown variable.
    Type: Grant
    Filed: March 25, 1986
    Date of Patent: February 21, 1989
    Inventors: John Kulli, Thomas M. Mitchell, Arthur E. Brown
  • Patent number: 4802363
    Abstract: A flotation device inside an elongate frame rises to the level of a liquid whose depth is being measured. The flotation device is locked in the frame while the apparatus is withdrawn from the liquid. The liquid level may then read from a scale on the frame.
    Type: Grant
    Filed: August 3, 1987
    Date of Patent: February 7, 1989
    Inventors: John J. Fling, William F. Fling
  • Patent number: 4801206
    Abstract: A dither flexure is mounted between a ring laser gyroscope body and a support such that the ring laser gyroscope may be dithered to have angular oscillations about a sensing axis. A sensor provides signals indicative of the amplitude of the oscillations of the ring laser gyroscope body relative to the support to a control circuit. The control circuit dithers the flexure to maintain the amplitude of the oscillations between a predetermined range at the resonant frequency of the flexure. The frequency of the dither oscillations is modulated about a tracking frequency, and the effect of frequency changes in the dither drive signal on the amplitude of the oscillations is demodulated to determine the resonant frequency of the dither flexure.
    Type: Grant
    Filed: June 4, 1986
    Date of Patent: January 31, 1989
    Assignee: Litton Systems, Inc.
    Inventor: Rodney W. Benoist
  • Patent number: 4799752
    Abstract: The apparatus according to the invention is all-fiber optic device that produces an output indicative of the gradient of an acoustic wave in water. The device comprises a neutrally buoyant body having a relatively rigid outer case. When it is submerged in water, the motion of the case is the same as that of a water particle in the same vicinity. A fiber optic linear accelerometer produces a signal proportional to the component of acceleration.
    Type: Grant
    Filed: September 21, 1987
    Date of Patent: January 24, 1989
    Assignee: Litton Systems, Inc.
    Inventor: Edward F. Carome
  • Patent number: 4797031
    Abstract: A caisson sinking method comprises the steps of excavating the ground to make a support ditch having the same plan-view shape as a caisson to be sunk, casting into the excavated ditch a bearing material that can carry the caisson as supported in the ditch but collapses easily by itself, placing entire tapered bottom edge of the caisson on the bearing material cast in the support ditch as aligned therewith, and sequentially removing the bearing material immediately below the bottom edge of the caisson, the caisson being thereby smoothly sunk down to a caisson sinking position without any tilting of the caisson.
    Type: Grant
    Filed: March 20, 1987
    Date of Patent: January 10, 1989
    Assignee: Daiho Construction Co., Ltd.
    Inventors: Hakumi Hagimoto, Yutaka Kashima, Norio Kondo, Masami Inoue
  • Patent number: 4792956
    Abstract: The actual values of intensity and wavelength of the optical signal output from a laser diode are compared to desired values thereof to generate intensity and wavelength error signals. The rates of change of the wavelength and intensity as functions of temperature and injection current about nominal operating values of the temperature and injection current are determined and used to calculate an injection current error signal and a temperature error signal for adjusting the injection current and temperature, respectively. The time response of the injection current and temperature are decoupled, which allows independent adjustment of the time constants of the exponential expressions for injection current and temperature. Providing independent adjustment of the time constants of the injection current and temperature variations permits the desired signal wavelength and intensity to be obtained in a time efficient manner.
    Type: Grant
    Filed: May 13, 1986
    Date of Patent: December 20, 1988
    Assignee: Litton Systems, Inc.
    Inventor: George W. Kamin
  • Patent number: 4790657
    Abstract: A dither flexure for a ring laser gyroscope includes a central portion and a plurality of curved vanes extending therefrom to connect to a flexure ring. The flexure ring includes a boss in a central portion thereof. A glass ceramic ring having a pair of end bosses is bonded to the boss around the flexure ring with the end bosses facing outward toward the ring laser gyroscope frame. The end bosses contact the ring laser gyroscope frame so that a void is formed opposite the flexure ring boss, which prevents transmission of radially directed stresses from the dither flexure to the frame. The curved blades have high resistance to off-axis vibrations and have high off-axis resonant frequencies so that very little coning and axis sag occur. Each blade has a curved portion and a straight portion, which provides a convenient location for mounting piezoelectric drive elements for dithering the ring laser gyroscope.
    Type: Grant
    Filed: March 18, 1986
    Date of Patent: December 13, 1988
    Assignee: Litton Systems, Inc.
    Inventor: William Kozma
  • Patent number: 4789240
    Abstract: This invention includes a fiber optic interferometer having a reference arm isolated from a physical parameter being monitored and a sensing arm exposed to the physical parameter being monitored. The sensing arm produces changes in the relative phase of the optical signals propagating in the sensing and reference arms in response to changes in the physical parameter. The sensing and reference signals are combined to produce an interference pattern after the sensing signal has been exposed to the physical parameter being monitored. A frequency shifter changes the frequency of the optical signal input to the interferometer, which produces interference signals at two frequencies.
    Type: Grant
    Filed: May 28, 1985
    Date of Patent: December 6, 1988
    Assignee: Litton Systems, Inc.
    Inventor: Ira J. Bush
  • Patent number: 4784453
    Abstract: A ladder architecture comprises an input optical fiber bus and an output optical fiber bus. A plurality of input optical couplers couple light between the input bus and a plurality of branching fibers. A plurality of output couplers couple light from the branching fibers to the output bus. The input bus and the branch fibers may be single mode optical fibers while the output bus a multimode optical fiber. The input couplers may be symmetrical, single mode devices, and the output couplers may be asymmetrical and single mode to multimode devices. The input bus may also be a multimode fiber, and the input couplers may also be multimode to single mode devices. The asymmetrical coupling reduces the amount of signal lost at fiber ends.
    Type: Grant
    Filed: February 2, 1987
    Date of Patent: November 15, 1988
    Assignee: Litton Systems, Inc.
    Inventors: H. John Shaw, Behzad M. R. Moslehi
  • Patent number: 4779985
    Abstract: A dither suspension for a ring laser gyroscope includes a central hub and a plurality of blades extending therefrom. One half of the blades are connected to a support ring, and the other half are connected to a support base that is fixed to the case. The support ring includes a boss extending from the ends thereof facing outward toward the ring laser gyroscope frame. The bosses contact the ring laser gyroscope frame so that a void is formed between the bosses and the frame, which prevents transmission of radially directed stresses from the dither flexure to the frame.
    Type: Grant
    Filed: December 22, 1986
    Date of Patent: October 25, 1988
    Assignee: Litton Systems, Inc.
    Inventor: Thomas M. Wirt
  • Patent number: 4778239
    Abstract: A lattice includes a transmit bus formed of a single mode optical fiber and a return bus formed of a multimode optical fiber. An optical transmitter applies input signals to the transmit bus, and an optical receiver receives the signals guided by the return bus. The return fiber is looped around the couplers so that the signal output from each segment of the lattice passes through all the preceding segments before reaching the receiver. The optical couplers have asymmetric coupling efficiencies so that recirculating light is attenuated.
    Type: Grant
    Filed: February 2, 1987
    Date of Patent: October 18, 1988
    Assignee: Litton Systems, Inc.
    Inventors: H. John Shaw, Behzad M. R. Moslehi
  • Patent number: 4775216
    Abstract: A fiber optic sensor array comprises a single transmit optical fiber for guiding an incident optical signal through a plurality of sensing segments in the transmit optical fiber arranged in a series array. The sensor array may includes a single return optical fiber, or the sensors may be arranged in groups with all the member of one group being connected to a corresponding return fiber. Optical couplers formed between the transmit and return optical fibers couple a portion of the incident signal into the return fiber after the signal propagates through each sensing segment. A loop is formed in the transmit fiber at each optical coupler so that the incident signal travels through the sensing segments in one direction and through the return fiber in the opposite direction. The couplers may be identical and may be have either symmertical or asymmetrical coupling coefficients. Asymmetrical couplers may be used to attenuate the intensities of undesired signals that recirculate in the loops of the array.
    Type: Grant
    Filed: February 2, 1987
    Date of Patent: October 4, 1988
    Assignee: Litton Systems, Inc.
    Inventor: Michael R. Layton
  • Patent number: 4755057
    Abstract: The present invention provides for initializing the particular intensity peak selected to operate about, based upon the initial temperature of the gyroscope in order to maintain a selected integer number of wavelengths as the initial cavity path length from start up to start up. In addition, the present invention provides an optimum available movement of the mirrors due to changing the voltage over the available voltage swing for the anticipated range and direction of temperature changes from the start up temperature, over which the gyroscope is expected to operate.
    Type: Grant
    Filed: September 5, 1986
    Date of Patent: July 5, 1988
    Assignee: Litton Systems, Inc.
    Inventors: Robert D. Curby, Rodney W. Benoist, Masao Yashimoto
  • Patent number: 4753529
    Abstract: Intensity modulated incoherent light is input to an interferometer. The interferometer is preferably formed to have a first arm comprising a first optical fiber and a second arm comprising a second optical fiber. The fibers have an initial optical pathlength difference .DELTA.L.sub.o. The refractive index of a selected one of the optical fibers is determined, and the output of the interferometer is monitored to detect a null signal output with an initial predetermined frequency resolution bandwidth. The initial length resolution is calculated, and the length of one of the fibers is reduced. The frequency resolution bandwidth is then reduced to a new predetermined value, and the frequency providing a null signal output at the new frequency resolution bandwidth is measured. The process is repeated until the pathlength difference becomes a predetermined value.
    Type: Grant
    Filed: June 23, 1986
    Date of Patent: June 28, 1988
    Assignee: Litton Systems, Inc.
    Inventor: Michael R. Layton
  • Patent number: 4753507
    Abstract: A fiber squeezer includes a frame that applies a preload to an optical fiber to permit variation of the birefringence thereof by either increasing or decreasing the preload. The optical fiber and a piezoelectric transducer are retained in the frame, and an appropriate voltage source is connected to the piezoelectric transducer to control the force on the fiber, which controls the refractive indices of the fiber by means of the photoelastic effect. The frame may include a pair of generally L-shaped legs fastened together to enclose the piezoelectric transducer and the fiber. The relative positions of the legs are adjustable during assembly of the frame to permit application of the preload to the fiber and transducer fiber squeezer. The frame may also include a generally U-shaped member having a pair of outwardly extending legs with an end plate mounted therebetween. The transducer and the fiber are held between the end plate and the lower portion of the U-shaped member.
    Type: Grant
    Filed: January 7, 1986
    Date of Patent: June 28, 1988
    Assignee: Litton Systems, Inc.
    Inventors: Ramon P. DePaula, John Turley
  • Patent number: 4740083
    Abstract: The present invention provides for initializing the particular intensity peak selected to operate about, based upon the initial temperature of the gyroscope in order to maintain a selected integer number of wavelengths as the initial cavity path length from start up to start up. In addition, the present invention provides an optimum available movement of the mirrors due to changing the voltage over the available voltage swing for the anticipated range and direction of temperature changes from the start up temperature, over which the gyroscope is expected to operate.
    Type: Grant
    Filed: October 2, 1984
    Date of Patent: April 26, 1988
    Assignee: Litton Systems, Inc.
    Inventors: Robert D. Curby, Rodney W. Benoist, Masao Yashimoto
  • Patent number: 4738511
    Abstract: A fiber optic coupler is formed by heating juxtaposed optically flat surfaces formed on two lengths of optical fiber to the glass transition temperature. The fibers bond together while preserving the molecular composition of the fibers at bonded region. Depending upon the depth to which the fibers are lapped to form the optically flat surfaces, the coupler may be either an evanescent field coupler or a core intercept coupler. The fibers may be mounted on curved substrates and then lapped to form the optically flat surfaces. The optical throughput of a fiber may be monitored during assembly of a coupler to permit adjustment of the positions of the optically flat surfaces to produce a desired coupling efficiency. The fibers may then be bonded together by application of energy from a suitable coherent light source such as a CO.sub.2 laser.
    Type: Grant
    Filed: January 7, 1986
    Date of Patent: April 19, 1988
    Assignee: Litton Systems, Inc.
    Inventor: John J. Fling