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.

Abstract: A spool for receiving a fiber optic sensor coil is selectively fabricated of materials of different coefficients of thermal expansion to thereby mimic the anisotropic thermal expansion characteristics of a potted sensor coil. The spool can include one or a pair of planar flanges fixed to the end(s) of a central cylindrical hub. The hub is preferentially fabricated in part of a polymer while the flange(s) is of low coefficient of expansion material such as titanium to thereby approximate the differential thermal expansions of a potted sensor coil in the axial and radial directions, respectively.

Abstract: Apparatus and methods for detecting when the birefringent axes of two polarization preserving fibers have their ends oriented into a position to locate the respective axes at 45 degrees. A fusion splicer and a heating controller for the fiber sensing coil are added to a reciprocal interferometer to produce a predetermined pattern of percent light intensity versus time in the returned light, when the axes are properly aligned for fusing. A computer may control the automatic making of depolarizers by this invention.

Abstract: Disclosed herein is a Ring Laser Gyroscope Enhanced Resolution System comprising, in a preferred embodiment, a sampling frequency modulation phase-locked loop (or "chirp") which is used in combination with the fast filter. Enhanced resolution is achieved by using the fast filter (preferably a moving average digital filter) to gather optically integrated rate data and accumulate this data. During the data gathering process, the accumulated data is sampled at a rate set by a frequency modulated ("chirper") phase-locked loop in order to remove undesirable data due to aliasing effects upon the digital filter. In this manner, an enhanced resolution of the gyroscope angular measurement is achieved.

Abstract: An anode structure of the present invention provides radially disposed first vanes and radially disposed second vanes interdigitating with the first vanes. The first vanes and the second vanes are each interconnected by a first strap and a second strap, respectively. The first strap and the second strap are disposed coaxially on the same side of the vane structure and are generally rectangular in cross-section, having substantially parallel facing surfaces. Each of the vanes is generally T-shaped, with a relatively wide high capacitive first portion and a relatively narrow high inductive second portion. The first portion is disposed proximate to an axis of the cavity with the second portion extending radially outward therefrom. The anode structure has at least thirty anode vanes.

Abstract: A cable strain relief device is described comprised of a pair of disks each having an opening therein sized to allow a cable to be passed therethrough; and an arrangement to maintain the disks in a position relative to one another such that the openings are proximate and offset whereby cable passed through the openings is kinked and retained therebetween. The disks may be identical, the opening in each disk being offset from the disk center. The disks are positioned relative to one another to offset the openings therein. The preferred arrangement to maintain the disks in position relative to one another is a backshell and backnut assembly. The cable strain relief device, when used with a plurality of electrically conductive sheathed cables, provides, where electrically conductive disks are used, an electrically conductive pathway between the plurality of cables to ground.

Abstract: A method for producing a narrow band anti-reflective film on a substrate, and the film produced by that method. The improved method being the concept of trimming the outer layer in order to correct for its thickness layers as well as those of the inner layer.

Abstract: A flood beam electron gun is provided for use in remediation of hazardous volatile organic compounds (VOC) contained within a detoxification vessel. The flood beam electron gun comprises an electron emitter having a rounded emitting surface providing a conical electron beam. A control grid is spaced from and disposed substantially parallel to the emitting surface. The control grid has a plurality of holes disposed in a first pattern providing an array of individual electron beams from the conical electron beam of the emitter. An intermediate electrode is spaced from the emitter and the control grid, and has an aperture therethrough providing a substantially parallel flow of the array of individual electron beams. A target grid is spaced from the intermediate electrode and opposite from the cathode and control grid. The target grid has a plurality of holes disposed in a second pattern that is proportional to and substantially larger than the first pattern.

Abstract: A tapered optical fiber component is provided that has an optical fiber with a cladded region. An optical core passes through the cladded region. The cladded region has a tapered extended first region drawn down in diameter to form an effective area region that has a predetermined effective area. The tapered extended first region is formed to adiabatically concentrate an optical signal for propagation through the effective area region of reduced diameter. The power density of the optical signal propagating through the effective area region is increased as an inverse function of the effective area.

Abstract: An accelerometer is fabricated by forming a proofmass and at least one associated hinge in a silicon substrate through a variety of a etching and bonding processes is disclosed. The processes entail ion implantation and formation of an oxide support layer below the proofmass, integrally bonding two complementary proofmass and substrate structures together, and then removing the oxide support layer to leave the proofmass supported by the hinge within the body of silicon material. The proofmass may be electrically connected to a lead extending through an etched recess in one of the substrates, and the proofmass may be electrically isolated or separated from the substrates by an oxide layer and by a change in conductivity type of the semiconductor material wherein the hinge is structurally mounted to the substrates. In a bond and etch back process, the wafer is processed, sawed in half, and then bonded together again wherein the complementary halves are joined to obtain the finished accelerometer.

Abstract: In a closing switch having a control electrode and a cathode within a gas-filled cavity, the cathode has a distal portion spaced from the control electrode by a distance corresponding to the minimum breakdown voltage of the closing switch. Thus, the cathode is placed such that gas breakdown adjacent the distal portion occurs at a control voltage lower than the voltage required to initiate such breakdown adjacent the portion of the cathode closest to the control electrode.

Abstract: A force balanced accelerometer system comprises an accelerometric sensor and a control system. The sensor comprises a conductive pendulum pivotably mounted between first and second electrode plates. The control system establishes a cycle period with three phases. In the first phase, the pendulum is electrically isolated in an electric field established between the electrodes. The pendulum is moved from a null position in response to inertial acceleration, and a pickoff signal indicative of the acceleration-responsive position is generated. The pickoff signal is fed into a sample-and-hold circuit and then into a servo compensation circuit, having proportional and integral control, so as to generate a force-indicative signal indicative of the magnitude and direction of the force required to restore the pendulum to the null position.

Abstract: A flip-up mount is provided for a night vision system. The mount comprises a carriage which is configured to engage a coupling device provided on the night vision system and secure the system in place. A pivotal armature is attached to the carriage and extends from a pivot point. The armature pivots between a first operational position enabling an operator to use the system, and a second stowed position. An anchor secures the pivot point to a helmet worn by the operator of the system. The pivot point further comprises a brace having an axle shaft, a sleeve integral to the armature and rotatable about the shaft, and a spring biased locking member securing the sleeve in a selected one of the first and the second positions. A supplemental chin strap is provided to prevent unwanted movement of the helmet when the night vision system is in the stowed position. Alternatively, the flip-up mount can be used in conjunction with a face mask worn by the operator.

Abstract: Disclosed herein is a multi-pole magnetic geometry for a multi-oscillator ring laser gyroscope. Multi-pole magnetic geometry configurations are disclosed which are useful for providing Faraday rotation where the multi-oscillator uses a Faraday rotator and high magnetic field effect where the nature of the multi-oscillator ring laser gyroscope is of split gain configuration. The multi-post magnetic geometry includes a plurality of top or bottom loaded diametrically opposed north and south pole axially directed magnets which are positioned substantially transverse to the optical pathway but suitable for providing axially directed magnetic fields to portions of the optical pathway only where desired. The multi-pole magnetic geometry disclosed herein substantially produces a magnetic flux that is restricted in its position to localized portions of the optical pathway with low far field effects.

Abstract: An extended interaction output circuit is provided for interacting with a modulated electron beam and for outputting RF electromagnetic energy. The circuit comprises a plurality of linearly disposed cavities having an axially extending beam tunnel to permit the traveling therethrough of the modulated electron beam as well as to couple electromagnetic energy between the successive cavities. Each of the cavities is separated by an annular disk having a hole providing the axial beam tunnel. The hole diameters increase in steps so that the impedance of the successive cavities decreases along the axial extent of the circuit. The diameter of the successive cavities is also increased as the associated width is decreased to maintain the same mid-band resonant frequency. The linearly disposed cavities act as an RF filter having successively tapered impedances to reduce reflections of the electromagnetic energy propagating through the circuit.

Abstract: A leaky wall filter for use in an EIK comprises a plurality of guidelets intersecting perpendicularly with a wall of an output waveguide of the EIK. The guidelets would propagate 2.pi. mode oscillation frequencies from the EIK out of the output waveguide. A load matched to the 2.pi. mode disposed at the end of the guidelets provides termination for the 2.pi. mode oscillation frequencies and prevents the initiation of oscillation. The load comprises a plenum disposed at an end of the guidelets opposite to the output waveguide, a window having a first surface within the plenum, and a water load provided at a second surface of the window. The 2.pi. mode oscillation frequencies propagating through the guidelets are impedance matched by the window and coupled into the water load for termination. Since a portion of the operating frequency power also leaks through the guidelets into the plenum due to insertion loss, this combined RF power also couples into the water load and is converted into thermal energy.

Abstract: A capacitive stub for adjusting an impedance level of an output gap of a klystron is provided. The klystron includes an iris coupling RF power from the klystron to an output waveguide. The capacitive stub extends from an inner surface of the output waveguide into a position generally adjacent at least a portion of the iris. The stub is capable of adjustment from external to the output waveguide to vary the position of the stub relative to the iris, and in so doing, change the capacitance of the iris. By changing the iris capacitance, the impedance of the output gap can be altered.

Abstract: The apparatus of this invention uses a rectangular-parallelepiped prism to extract portions of the counterpropagating beams from a ring laser of a gyro. Such prism is easier to build than prisms having other than right angles. One beam bounces within the prism, but it is not perfectly reflected, and a portion of the beam is transmitted to a sensor to control the length of the ring laser cavity. The two beams are combined to produce a heterodyne signal by using two partly transmissive mirrors on two parallel surfaces of the prism, and by positioning a third side surface at a critical angle relative to one of the beams.

Abstract: A diode laser apparatus is heated at its junction by operating the diode at subthreshold current levels. A special bi-level pulse forming network (PFN) improves the efficiency in preheating the diode during non-operating or non-light producing modes along with the ability to supply the necessary drive during operating or light producing modes. This is accomplished by operating the laser diode at subthreshold or non-light producing current levels, which heats the diode at the diode junction directly where the heat is needed, and by the use of a bi-level pulse forming network which transfers the heating energy to the diode junction with high efficiency.

Abstract: An advanced center post (ACP) gun is provided which is capable of producing either a large orbit or small orbit electron beam. The gun comprises an annular shaped cathode, a control electrode adjacent the cathode, and an annular anode having an opening therethrough. A center post is disposed axially within the center region of the cathode and the control electrode along a center line of the electron gun and interaction region of a microwave device. The anode is shaped in conjunction with the center post to control position of equipotential lines of an electric field provided in an inter-electrode space between the cathode and the anode so that an electron beam emitted by the cathode converges at the anode opening. The control electrode provides electrostatic focusing of the beam to further control the beam convergence. Multiple polepieces provide accurate control of the magnetic field in the interaction region to shape the beam and control the orbit size and velocity spread.