Abstract: A ferromagnetic material on an optical fiber assures that the fiber is held n a proper position on a spool by a magnetic field. This stabilizes the optical fiber during winding to permit an automation of the spooling process and provides a constant force for holding the spooled optical fiber during storage. The constant and predictable holding force helps assure a constant and predictable peel force during deployment of the optical fiber.

Abstract: A system for detecting intrusion into a secured environment using both fixed and mobile intrusion detectors includes a multiplicity of fixed intrusion detection sensors are each deployed at specific, fixed locations within the environment. The mobile sensors are mounted on one or more mobile platforms which selectively patrol throughout the environment and may be rapidly deployed to any region in the environment where a fixed intrusion detector detects a possible intrusion. A computer receives the outputs of the fixed and mobile sensors and is communicatively coupled to the mobile platforms. The computer directs the mobile platforms to travel through the environment along paths calculated by the computer, calculates a sum of weighting factors associated with the output of each sensor, and fuses the sensor outputs so that the sum is uninfluenced by the traveling of the mobile platforms. The sum is compared to a reference whereby an output is provided when the sum exceeds the reference.

Abstract: The 1.06.mu. Nd transition in a co-doped Cr,Nd:Gd.sub.3 Sc.sub.2 Ga.sub.3 sub.12 (Cr,Nd:GSGG) gain element is obtained by diode pumping Cr.sup.3+ at 670 nm and produces efficient, low threshold laser operation. Although co-doped Cr,Nd:GSGG was developed for more efficient flashlamp pumping, it has the desirable property of having an extraordinarily broad absorption to allow for efficient diode pumping relative to the Nd:YAG laser. The consequent broad bandwidth tolerance of the Cr,Nd:GSGG for the diode pumping radiation allows diode pumping of the 1.06.mu. transition without regard to the wavelength of the visible diodes which has the potential for reducing the cost of the semiconductor pump and also demonstrates the extended versatility of these diodes which previously had been restricted to pump the Cr.sup.3+ tunable vibronic lasers. CW and long pulse diode pumping provided pump power levels as high as 300 mW cw and 1 W pulsed. The lowest threshold power was measured at 938 .mu.

Abstract: A method and apparatus for characterizing the quality of an electrically thin semiconductor film and its interfaces with adjacent materials by employing a capacitor and a topside electrical contact on the same side of the electrically thin semiconductor film to thereby permit the taking of capacitance-voltage (C-V) measurements. A computer controlled C-V measuring system is operatively coupled to the contact and capacitor to modulate the potential on the capacitor. Variation of the voltage applied to the capacitor enables modulation of the potential applied to the film to thereby vary the conductivity of the film between the capacitor gate node and the topside contact.

Abstract: An optically powered photomultiplier tube is provided, comprising a vacuum chamber having a window for incident optical radiation which is to be detected; a photocathode to receive the optical radiation; an electron multiplier system within the chamber to amplify the electron current from the photocathode; an anode to receive the amplified electron current; a high voltage photocell array positioned within the chamber for generating high voltage electrical power that is provided to the electron multiplier system; a system for delivering optical power to the photocell array; a first electrical contact penetrating the container in a vacuum tight manner and operably coupled to the anode; and a second electrical contact penetrating the container in a vacuum tight manner and operably coupled to the photocell array.

Abstract: An optical blue parametric generation relies upon a nonlinear optical cryl of lithium borate (LiB.sub.3 O.sub.5) properly oriented to generate blue light when appropriately located in a resonant optical cavity and pumped with high intensity light at 355 nm. Beam walk-off and beam pump divergence are greatly reduced due to a specific orientation of non-critical phase-matching so that the 355 nm pump source provides for a sufficient phase-match for output generation near the H Beta Fraunhofer wavelength at 486 nm and also provides for a temperature tuning of the lithium borate crystal to permit exact coincidence to a particular output wavelength so that optical parametric generation from 470 to 487 nm may be assured by the appropriately tuned lithium borate crystal.

Abstract: An apparatus determines the location of a signal source having coordinates x,y). The source may be located as far away as two thousand km and does not require knowledge of ionospheric height or layer structure. The apparatus comprises at least three receivers adapted to receive the signals from the signal source. The coordinates, (x.sub.1,y.sub.1), (x.sub.2,y.sub.2) and (x.sub.3,y.sub.3), of each of the receivers are very precisely known. One receiver is capable of receiving signals from the other two receivers through different means (e.g. a wide-band telephone link). A plurality of at least three timers, one connected to each receiver, measures precisely the time difference of arrival (TDOA) of the signals from the signal source. A plurality of at least three means, connected one to each of the receiving means, determine the vertical angles .phi. at which the signal from the signal source is received by each of the receivers.

Abstract: A high data rate over-the-horizon communications capability is provided been two or more platforms at rest or in motion, in the air or on the surface. An RF transmitter/receiver-optical fiber interface unit is launched from a launch platform and is supported via a deployed parachute or balloon to provide a bidirectional RF data link with the launch platform and a bidirectional optical data link over an optical fiber extending to an autonomous vehicle platform, such as a missile.

Abstract: A method of emitting on a specific wavelength Fraunhofer line of peak seawater transmission and minimum solar radiation is disclosed. This method includes the steps of emitting at least on a specific wavelength of an infrared transition line from a neodymium gain element in an optical resonator; frequency tripling the infrared line from the resonator to a specific ultraviolet wavelength in a frequency multiplier; and Raman down shifting the specific ultraviolet wavelength a predetermined degree by a predetermined number of Stokes shifts in a predetermined medium in a Raman shifter to produce a high peak-power output at the specific wavelength Fraunhofer line.

Abstract: An array for receiving wave energy at a pair of widely spaced frequencies has receiving elements arranged to function as a half-wave array for the lower frequency and as a random array for the higher frequency. A plurality of receiving elements are arranged in an array with the receiving elements having nominal positions spaced apart such that spacing between adjacent nominal positions is approximately one half the wavelength .lambda. of the wave having the lower frequency. The receiving elements are randomly distributed about their respective nominal positions with each receiving element being within a distance of .epsilon..lambda..sub.o of its corresponding nominal position where .epsilon. is a randomization parameter and .lambda..sub.o is the wavelength of the higher frequency wave.

Abstract: A chromium doped solid-state high peak-power laser transmitter emits at a 4861.342 or 4340.50 Angstrom Fraunhofer line, lines of peak blue-seawater transmission and minimum solar radiation. A pink ruby gain medium doped with approximately 0.05% chromium ion is temperature tuned to an R2 line at 6924.51 Angstrom wavelength and an R1 line is dispersively suppressed in a laser oscillator cavity also tuned to 6924.51 Angstrom. The oscillator is Q-switched and the amplified high peak-power 6924.51 Angstrom R2 line output is frequency doubled to 3462.26 Angstrom and hydrogen Raman down-shifted 8310 cm.sup.-1 to the second-Stokes at 4861.342 Angstrom to produce said high peak-power output centered on the 4861.342 Angstrom hydrogen-beta Fraunhofer line. Optionally, a temperture tuned 6927.00 Angstrom R2 line laser oscillator wavelength from the pink ruby gain medium doped with approximately 0.05% chromium ion relies on frequency doubling the R2 line at 6927.00 Angstrom to 3462.

Abstract: A chromium doped solid-state high peak-power laser transmitter emits at a 4861.342 or 4340.5 Angstrom Fraunhofer line, lines of peak blue-seawater transmission and minimum solar radiation. A pink ruby gain medium doped with approximately 0.05% chromium ion is temperature tuned to an R2 line at 6924.51 Angstrom wavelength and an R1 line is dispersively suppressed in a laser oscillator cavity also tuned to 6924.51 Angstrom. The oscillator is Q-switched and the amplified high peaked-power 6924.51 Angstrom output is hydrogen Raman shifted to the first-Stokes at 9722.684 Angstrom which is frequency doubled to produce a high peak-power output at 4861.342 Angstrom hydrogen-beta Fraunhofer line. Optionally, a temperature tuned R2 line at 6927.00 Angstrom wavelength from the pink ruby gain medium doped with approximately 0.05% chromium ion is Raman shifted 2916 cm.sup.-1 in methane to the first-Stokes at 8681.0 Angstrom. Next, the first-Stokes at 8681.0 Angstrom is frequency doubled to the 4340.

Abstract: The present invention provides a pneumatically powered actuator having hydraulic control for both locking and controlling the velocity of an output rod without any sponginess. The invention includes a double-acting pneumatic actuator having a bore, a piston slidably engaged within the bore, and a control rod connected to the piston. The double-acting pneumatic actuator is mounted to a frame. A first double-acting hydraulic actuator having a bore, a piston slidably engaged within the bore, and a follower rod mounted to the piston is mounted to the frame such that the follower rod is fixedly connected to the control rod. The maximum translation of the piston within the bore of the first double-acting hydraulic actuator provides a volumetric displacement V.sub.1. The present invention also includes a second double-acting hydraulic actuator having a bore, a piston slidably engaged within the bore, and an output rod mounted to the piston.

Abstract: A Frequency Dispersive Transmitting Array (30) for propagating composite e energy (10) emulates narrow-band beams (20) of different frequencies which can be simultaneously radiated in all directions, or in any subset of directions, relative to an array (42) of radiating elements (32) because of the addition and cancellation of components of wave energy (10) radiated, is disclosed. A signal source (34) provides input signals (36), having frequencies which may be acoustic or electromagnetic, which are coupled by feedline (37) to radiating elements (32) through a plurality of time delay devices (38). Each one of time delay devices (38) is interposed between successive ones of radiating elements (32) and delays emission of replicas of signals (36) therefrom by a time delay .tau..sub.0 which is a multiple of the period of the dominant frequency radiated in a direction broadside to the array.

Abstract: An apparatus and method for non-contact sensing electrical potentials of selected regions on the surface of a sample are provided. A typical sample is an integrated circuit, electronic device, or semiconductor material. The sample is positioned within a vacuum chamber and irradiated with an ultraviolet light beam so that the material emits electrons by the photoelectric effect. The electrons have kinetic energies which are variable according to the electrical potential of the surface of the material. Emitted electrons having kinetic energies within a predetermined range are selected by an electron energy analyzer. An electron detector receives the selected electrons and produces electrical signals corresponding to the energies of said selected electrons. In another embodiment of the invention, a modulated light beam other than the ultraviolet light probe beam irradiates the material in order to produce time varying modulation of the photoelectron energy spectrum.

Abstract: A signal phase pattern sensitive neural network system can discern persist patterns of phase in a time varying or oscillatory signal. The system employs duplicate inputs from each of its sensors to the processing elements of a first layer of its neural network, with the exception that one input is phase shifted relative to the other. The system also employs a modification of a conventional Kohonen competitive learning rule which is applied by the processing and learning elements of a second layer of its neural network.

Abstract: A visual display system provides patterns for visually aiding an operator determining the nature and noise environment of the incoming signal. A conventional signal receiver and an oscilloscope are coupled to a phase detector, a clock circuit and a frequency synthesizer. The clock circuit synchronizes the operation of the receiver, phase detector and frequency synthesizer. The phase detector includes a digital delay means for imparting a digital time delay between two signals and has two outputs connected to the X and Y deflection terminals of the oscilloscope screen for effecting a display in a lissajous form and another, third output connected to the Z terminal to vary the intensity of a part of the screen such that patterns are generated on the oscilloscope that might represent the inherent nature of the incoming signal which might include, the type of noise, the presence of doppler shift or CW interference, or drift of a component.

Abstract: An apparatus for a method for assuring the secure transmission of information between a transmitter and a receiver is fabricated along the lines of a Mach-Zehnder interferometer. Two, identical length single-mode fibers extend between the transmitter and receiver to act as transmission paths. Within the transmitter a coiled length of like single-mode fiber integrally extends from one of the fibers reaching from the transmitter to the receiver. Within the receiver a like length of like single-mode fiber integrally extends from the other end of the other fiber reaching from the transmitter to the receiver. A superradiant diode in the transmitter emits pulses of coherent wavetrains that are split and sent through the two lengths of fibers and their associated integrally connected coils.

Abstract: An acoustic source apparatus has a acoustic transducer that is enclosed in substantially rigid and watertight enclosure to resist the pressure of water on the transducer and to seal the transducer from the water. The enclosure has an opening through which acoustic signals pass and over which is placed a resilient, expandable and substantially water-impermeable diaphragm. A net stiffens and strengthens the diaphragm as-well-as constrains the diaphragm from overexpansion or from migrating due to buoyancy forces. Pressurized gas, regulated at slightly above ambient pressure, is supplied to the enclosure and the diaphragm to compensate for underwater ambient pressures. Gas pressure regulated at above ambient pressure is used to selectively tune the pressure levels within the enclosure and diaphragm so that diaphragm resonance can be achieved. Controls are used to selectively fill, as-well-as vent the enclosure and diaphragm during system descent and ascent, respectively.

Abstract: A low probability of intercept radar apparatus and technique involving operation at the lower water vapor absorption resonance frequency of 22.2 GHz wherein the radar beam is shaped such that it is restricted to low altitude and short range coverage. The system is implemented by conventional radar techniques with the exception of the technique disclosed herein of operating at the lower water vapor absorption frequency in combination with utilizing a rotating shaped beam antenna system that restricts the radar beam to low altitude and short range coverage.