Abstract: A fluid detector system for identifying a fluid or detecting presence of a substance in a fluid. The fluid detector includes at least two optical conductors, optical detectors coupled to outputs from the optical conductors; and a comparer for comparing the outputs from the detectors. Each optical conductor has an outer reflective surface. A first one of the optical conductors has a section with at least a portion of its outer reflective surface removed. The comparer can determine an optical refraction index of fluid at the section of the first optical conductor which has the portion of the outer reflective surface removed.

Abstract: A programmable interface. The inventive interface is designed to be used with an interface controller and includes a first circuit for selecting one or more components from a plurality of components in response to at least one first control signal. A second circuit selectively connects the components in response to at least one second control signal. A third circuit selects a serial output mode or a parallel output mode of said components in response to at least one third control signal. In an illustrative implementation, the inventive interface is used as part of an IEEE 1149.1 bus architecture and includes a plurality of stages. At least one of the stages is associated with each of the components under test and includes circuitry for selecting an associated component. The second circuit includes circuitry within each stage for selectively connecting an associated component to a second component by outputting the output of an associated component or the output a previous stage as the output of the stage.

Abstract: A chemical sensing system and method. The system (10) includes a transmitter having a laser for providing a collimated beam of electromagnetic energy at a first frequency and a Q switch in optical alignment with the beam. The system further includes a crystal for shifting the frequency of the beam from the first frequency to a second frequency. A mechanism is included for shifting the beam from the second frequency to a third frequency in the range of 8-12 microns. The system includes a mechanism for switching the polarization state of the second beam and providing third and fourth beams therefrom. The third beam has a first polarization and the fourth beam has a second polarization. The second polarization is orthogonal relative to the first polarization. The frequency shifted third and fourth beams are combined to provide an output beam in the range of 8-12 microns. The output beam is transmitted and a return signal is detected by a receiver in the illustrative chemical sensing application.

Abstract: Flexible epoxy-based adhesive compositions which remain Theologically stable at room temperature in an uncured state comprise: (a) at least one flexible polyepoxide resin having a hardness not exceeding a durometer Shore D reading of 45 when cured with a stoichiometric amount of diethylene triamine (“DETA”); and (b) a substantially stoichiometric amount of at least one latent epoxy resin curing agent. Optionally, the adhesive composition may also incorporate one or more semi-flexible resins. Other optional components include fillers, thixotropic agents, and flexibilizers. The adhesive composition provicdes an epoxy-based adhesive composition that is storable for weeks as a single component mixture at room temperature, curable at temperatures ranging from about 100° C. to 125° C. in less than two hours, and flexible upon curing to temperatures as low as minus 50° C., exhibiting a durometer Shore A of less than about 95.

Abstract: An image stabilization system and method. The inventive system (100) includes an image sampling circuit (230) mounted on a platform (400) for sampling an image in response to timing control signals and outputting a plurality of imaging signals in response thereto. An azimuth resolver (310) detects vibration of the platform and providing a signal in response thereto. A microprocessor (540) adjusts the timing control signals to cause the image sampling circuit (230) to sample the image and thereby compensate for an effect of vibration on the image. In the illustrative embodiment, the microprocessor (540) includes software for compensating for vibration that causes image offset, compressed images, expanded images, and compression and expansion within a single field. The invention provides image stabilization in a purely electronic manner without the need for any moving parts that would typically require control hardware and a significant amount of space.

Abstract: A method for preparing a hollow tube of shrinkable polymeric material by providing a hollow tube in an expanded state and partially contracting a portion of the length of the hollow tube. A first length in the expanded state is folded over a second length in the partially contracted state. A body such as a length of electrical cable is inserted into the hollow tube, and the first length is unfolded so that it no longer overlies the second length. The first length and the second length are contracted to the fully contracted state over the body.

Abstract: An integrated module for an active antenna assembly is disclosed. The integrated module is switchable between a receive mode and a transmit mode and includes active components and a dual input wideband balun. The active components includes amplifiers and micro electro-mechanical system (MEMS) switches. The integrated module is adapted for positioning directly behind a radiator of an antenna array.

Abstract: An optical system has a light source of an optical beam, and a wavefront distortion generator that introduces a known wavefront distortion into at least one wavelength component of the optical beam prior to the formation of an intermediate image. A focusing device receives the optical beam, produces the intermediate image of the optical beam, and outputs the optical beam. A wavefront distortion corrector, after the formation of the intermediate image, introduces a wavefront distortion correction into each component of the optical beam into which the known wavefront distortion was introduced by the wavefront distortion generator. The wavefront distortion correction is the reverse of the known wavefront distortion introduced into the optical beam by the wavefront distortion generator.

Abstract: A radar system having a tactical mode and a calibration mode includes a transmitter section for providing high-power amplification of an RF pulsed waveform from an exciter during the tactical mode and the calibration mode. A circulator system has an input port connected to an output of the transmitter section and including first, second and third switchable junctions, and a high-power attenuator. The circulator system provides a transmit tactical mode signal path and a transmit calibration mode signal path of virtually identical electrical path lengths for a transmitter output signal, the tactical path passing through the first, second and third junctions in a first direction to an antenna I/O port, the calibration path passing through the first, second and third junctions in a second direction and through the high-power attenuator to an output port.

Abstract: An air-gap optical structure is fabricated by depositing a metallic spacer structure on a first transmissive optical element, and then contacting a second transmissive optical element to the spacer structure so that the spacer structure lies between the first transmissive optical element and the second transmissive optical element and defines an air gap therebetween. A first layer of the spacer structure contacts the first transmissive optical element, and a second layer of the spacer structure contacts the first layer. The first layer is preferably deposited by vapor deposition and is relatively thin, and the second layer is preferably electroless deposited and is relatively thick. The total thickness of the spacer structure is typically from about 5 to about 15 micrometers.

Abstract: An antenna and antenna excitation method. The inventive antenna includes a cylindrical array (20) of radiating elements. Each of the elements is mounted at a predetermined substantially transverse angle relative to a longitudinal axis. A circuit (30) is included for providing an electrical potential between at least two of the elements effective to scan a transmit or a receive beam of electromagnetic energy along an elevational axis at least substantially transverse to the longitudinal axis. In the illustrative embodiment, the array includes a stack of the planar, parallel, conductive, ring-shaped radiating elements, each of which is filled with ferroelectric bulk material. A second circuit (70) is included for exciting at least some of the elements to cause the elements to generate a transmit or a receive beam of electromagnetic energy off-axis relative to the longitudinal axis.

Abstract: A multi-layer anti-reflection coating for simultaneously coupling electromagnetic radiation of two different wavelengths, &lgr;1 and &lgr;2, where &lgr;1 is greater than &lgr;2, from a first region into a second region is provided. The first region has an index of refraction that is smaller than that of the second region. The anti-reflection coating comprises three layers: (a) a first layer and a third layer that are essentially invisible to &lgr;1 and serve to reduce Fresnel losses for &lgr;2 and (b) a second layer sandwiched between the first and third layers that serves to reduce Fresnel losses for &lgr;1. The thickness and the index of refraction are calculated for each layer.

Abstract: A situation awareness viewing device, typically in the form of a head-mounted display device, includes a polarizing beam splitter made of a cube of a material transparent to light and having an index of refraction greater than 1, and a wire grid polarizer lying within the cube on a cube-diagonal plane extending between two diagonally opposed edges of the cube. The polarizing beam splitter has a first optical axis extending from a first face of the cube toward an opposing second face of the cube and lying at an angle of 45 degrees to the cube-diagonal plane, and a second optical axis extending from a third face of the cube toward an opposing fourth face of the cube and lying at an angle of 45 degrees to the cube-diagonal plane, the second optical axis being perpendicular to the first optical axis.

Abstract: Composite structures having a single continuous skin may be formed using automated fiber placement methods. These composite structures include frameless aircraft fuselage components offering an increased interior cabin width over conventional fuselage components. The composite structures may be constructed of multiple layers of fibers and other materials placed on a fiber placement tool that includes a mandrel body surrounded by a bladder or an integral bladder/caul sheet having expansion spaces created within the caul sheet section. Uncured composite structures may be created by placing fibers around the fiber placement tool in a plurality of discontinuous segments that are capable of moving or sliding in relation to each other so that the uncured composite structure is expandable from within.

Abstract: A wave plate (10) formed of a perforated metallic plate of a particular thickness (L) has circular holes (12) that induce a change in the polarization of an electromagnetic wave passing through the holes in the plate. By choosing the proper hole diameter, the hole spacing in orthogonal directions, and the plate thickness, the desired relative phase shift is achieved with maximum transmission and minimal reflection. Two or more axially-aligned wave plates form a variable wave plate system. By changing the relative rotational positions of the wave plates, the polarization of the electromagnetic wave passing through the system can be selectively varied.

Abstract: An improved sigma-delta modulator is disclosed. The sigma-delta modulator utilizes Micro Electro Mechanical System (MEMS) technology coupled with on-chip LC networks. MEMS switches are used to switch capacitors and inductors in and out of the network to alter the center frequency and tuning range of the sigma-delta modulator, thus eliminating active components in each LC network. Furthermore, the use of MEMS switches improves the Q of each LC network relative to previous on-chip sigma-delta modulator designs. The increased Q of each LC network reduces or eliminates the need for active Q-enhancement circuitry and improves the inherent filter shape within the loop of the sigma-delta modulator. In addition, the distortion of active components with the loop of the sigma-delta modulator also is improved. The addition of a decimator to the chip presents a complete single chip LC sigma-delta analog-to-digital converter.

Abstract: Techniques for maintaining beam pointing for an Electronically Scanned Antenna (ESA) as its frequency is varied over a wide frequency bandwidth. A technique uses discrete phase shifters, a number of stored states, and a control methodology for rapidly switching among the states.

Abstract: The inventive rod includes a gain medium having first and second equal length portions sharing a common optical axis and an optical rotator disposed between said first and second portions which optical rotator compensates for birefringence. In an exemplary case, the optical rotator includes first and second waveplates optically coupled to one another and oriented with respect to one another by a predetermined angle, where the first waveplate receives a polarized beam having a first state, and the second waveplate produces the polarized beam having a second state, the first and second states differing from one another by 90°. Multiple rotators can be employed to compensate strongly birefringent rods, each rotator compensating a section of a rod constructed from a plurality of equal length optical gain elements.

Abstract: An optically-pumped laser having a gain medium configured to provide a low loss, three-dimensional integrated optical pump cavity that substantially confines optical pump radiation within the lasing volume, which is particularly useful for efficiently pumping solid state gain media that has low pump dopant concentration. The integrated pump cavity includes a plurality of boundaries contiguous with the gain medium. An optical pump source such as a laser diode array supplies optical pump radiation that is input into the gain medium through one or more pump cavity windows with a propagation direction transverse to a laser axis defined through the gain medium. In some embodiments, an optical surface is situated opposite the window to approximately recollimate the input pump radiation. The optical pump cavity may be designed to concentrate the optical pump radiation and approximately uniformly pump the entire volume of the lasing medium.

Abstract: A munition rack comprises a center strongback with an aircraft attachment hookup structure thereon, a first munition deployment structure, including a first munition deployer, affixed to a first outboard end of the center strongback, and a second munition deployment structure, including a second munition deployer, affixed to a second outboard end of the center strongback. The center strongback, the first munition deployment structure, and the second munition deployment structure are preferably dimensioned such that the distance between a first munition deployer transverse midpoint and a second munition deployer transverse midpoint is at least about 19 inches. There is at least one additional munition deployment structure selectively affixed to the bottom of the center strongback at an inboard location intermediate between the first outboard end and the second outboard end.