Abstract: This invention pertains to a method and apparatus for inscribing a pattern into a surface of a substrate, such as a sheet of glass. The method includes the steps of providing a Nd:YAG laser (12) having a characteristic output wavelength of 1.06 micrometers; providing a glass substrate (18) that is substantially transparent to the characteristic output wavelength; and applying a layer of material, such as a layer of tape (16), to a surface (18a) of the substrate. The layer of material is selected so as to strongly absorb the characteristic output wavelength. A next step focuses (14) an output of the laser into a spot (12c) at or near to an interface between the layer of material and the surface of the substrate. A further step translates (20) the surface relative to the spot. The layer of material absorbs the output of the laser and is heated thereby to a temperature sufficient for inscribing the surface underlying the spot.

Abstract: Systems that distribute live television programs to passengers of an aircraft by way of satellites of a direct broadcast satellite (DBS) system when the aircraft is in range of the satellites and distributes time-delayed television programs when the aircraft is out of range of the satellites. The present invention provides for real-time reception and storage of live television programs in a storage medium (in compressed digital format) and presentation to passengers during that time when the aircraft is within the coverage area of satellites. The stored programming is distributed to the passengers later in the flight, when the aircraft is out of range of the satellites. The stored programming includes all channels transmitted by the satellites. Thus, a large number of programs are made available to the passengers on a time-delay basis. A low-cost system is disclosed that distributes a single television channel to overhead monitors and headphones.

Abstract: A telemetry system for receiving data from large arrays of sensors, in which the sensors are located in an unprotected environment, is implemented using fiber optic components. Laser sources, located in a protected environment, transmit light through the boundary separating the protected environment from the unprotected one. The light is then split into a number of beams and fed to electro-optical modulators, where it is modulated in response to electrical signals received from the sensors. The modulated light signals are then wavelength-division multiplexed and transmitted back through the environment boundary, where they are amplified, demultiplexed and converted to electrical signals. Multiplexing reduces the number of boundary penetrations, and the use of highly stable electro-optical modulators eliminates the need for signal conditioning electronics at each sensor.

Abstract: A method and system of damping nutation of a spacecraft (20) having a desired spin axis along a first principal inertia axis utilizes a momentum source (28) oriented along a second principal inertia axis perpendicular to the first principal inertia axis. An angular rate of the spacecraft (20) is sensed along an axis transverse to both the first principal inertia axis and the second principal inertia axis. An angular rate signal representative of the angular rate is generated. The angular rate signal is processed to form a control signal representative of a desired torque to drive the momentum source. The desired torque has a first additive component proportional to a derivative of the angular rate to critically damp the nutation under an at least second order model of the spacecraft (20). The momentum source (28) is driven in dependence upon the control signal.

Abstract: A non-toxic coolant/lubricant suspension is provided which is specifically designed for use in extremely high-load, high-stress machine operations, such as broaching. The composition of this coolant/lubricant includes about 1 to 15 wt % of molybdenum disulfide (MoS.sub.2) powder; about 1 to 7 wt % of soap flakes; about 6 to 12 wt % of a liquid polytetrafluoroethylene suspension; and about 66 to 92 wt % water. The liquid polytetrafluoroethylene component, which is a water-based suspension of polytetrafluoroethylene, serves as a replacement for toxic CCl.sub.4, which has been used to increase lubricity in coolant/lubricants comprising molybdenum disulfide. The replacement of CCl.sub.4 with liquid polytetrafluoroethylene in the present composition results in a non-toxic but still highly effective coolant/lubricant.

Abstract: A differential nonlinear transmission line (NLTL) circuit has anti-parallel diode pairs along a balanced transmission line to generate well defined high-speed pulses with sharp positive and negative transitions from a time varying input signal. The input signal may carry an arbitrary DC bias voltage component that is suitable for digital logic circuits, such as current mode logic (CML) employing differential inputs.

Abstract: A system that provides live television programming to passengers by integrating direct broadcast satellite services into an in-flight aircraft entertainment system. The present invention is a satellite television system that has an antenna disposed on the aircraft that is pointed at a plurality of satellites that are part of a direct broadcast satellite system. The antenna is controlled by an antenna controller and antenna interface unit that send control signals and process status signals to steer the antenna. The antenna is steered to lock it onto RF signals transmitted by the satellites. The antenna interface unit downconverts the received RF signals to provide left hand circularly polarized RF signals and right hand circularly polarized RF signals that contain different sets of television channels. The downconverted RF signals are processed by a receiver/decoder that decodes them to provide video signals corresponding to different television channels.

Abstract: A projection system wherein two or more separate display sources, such as high brightness sources, or active matrix liquid crystal display (AMLCD) or other flat panel displays are used to write information directly onto a display screen, or onto a photoactivated reflective light valve for projection onto the display screen. Sequential imaging apparatus is used to alternately generate first and second images for display. For example, such images are coupled to the photoactivated reflective light valve and an illumination source is employed to illuminate the light valve and project a composite image onto the display screen. The flat panel displays may be transmissive, reflective, or self-emissive with the use of an optical shutter. A writing illumination source is used for non-self-emissive flat panel displays. Using high brightness display sources, the images may be directly written onto the display screen without the use of the reflective photoactivated light valve and the illumination source.

Abstract: A high power Er-doped fiber amplifier/laser system includes a cladding-pumped fiber grating laser that emits an output beam at a wavelength that falls within an absorption band of erbium. The fiber grating laser output beam is used as the pumping source for an Er-doped fiber amplifier or laser. Because the output from the fiber grating laser falls within one of the erbium absorption bands, the amplifier or laser may be directly pumped with the fiber grating laser's output without the need for co-doping. In a preferred embodiment, the fiber grating laser is a 980 nm ytterbium-doped fiber grating laser that is cladding-pumped with a multi-transverse mode diode laser array. The Yb-doped fiber grating laser and the Er-doped fiber amplifier/laser are preferably spliced directly to an input and output arm of a WDM fiber coupler, respectively.

Abstract: An integrated digital circuit is protected from reverse engineering by fabricating all transistors of like conductivity with a common size and geometric layout, providing a common layout for different logic cells, connecting doped circuit elements of like conductivity with electrically conductive doped implants in the substrate rather than metalized interconnections, and providing non-functional apparent interconnections that are interrupted by non-discernable channel stops so that all cells falsely appear to have a common interconnection scheme. The camouflage is enhanced by providing a uniform pattern of metal leads over the transistor array, with a uniform pattern of heavily doped implant taps from the transistors for connection to the leads; undesired tap-lead connections are blocked by channel stops.

Abstract: A simple, low-cost deformation mechanism and method produces submicrometer increments of motion, to precisely stretch and compress fibers containing optical gratings in order to achieve a desired length and period. Such a "tunable" fiber can be used to, for example, produce an optical filter or to "match" two fiber lasers, thus enabling their use in a coherent detection system. Two beams, parallel to and opposing each other, are joined at two places. A screw is positioned between the beams such that a force is exerted on both beams simultaneously when the screw is rotated, deforming both beams. Motion reduction is provided by sharing the screw's movement between the two beams, and is further enhanced by making one beam thicker than the other. Two fibers are secured into grooves provided on one of the beams. By rotating the screw to increase or decrease the deformation, the fibers and their respective gratings are stretched or compressed.

Abstract: Systems (10, 10a) and a methods (40) that employ a spin-stabilized spacecraft (12) in combination with a support and deployment module (14) to carry a plurality of probes (16) containing scientific instruments that are to enter a planet's atmosphere and/or are to be landed on a planet (19) that is to be explored. The spacecraft (12) functions as a probe carrier using the support and deployment module (14), and near the planet (19), it functions as an orbiting communications satellite (12) that relays data and commands between the aerocraft (16) and Earth. The support and deployment module (14) secures the probes (16) and is interposed between the spacecraft (12) and the launch vehicle (11). The support and deployment module (14) passes all structural loads due to the added mass of the aerocraft (16) directly to the launch vehicle (11), which is designed (nominally) for the total launch mass, and does not impose any structural loads on the satellite (12).

Abstract: A mobile, satellite-based communication system includes a defined signaling arrangement developed from an analysis of factors including movement of the mobile terminals, movement of the satellite, beam discrepancies and duration of the call to the mobile terminal to set up a frame assignment plan for time division multiple access (TDMA) carriers and identifying permissible frame offset which can be accommodated throughout the entire transmission. As a result, timing and frequency references from a mobile to mobile command (MMC) may be provided from a reference source along with receive and transmit data communications without losing the command signals or the communication information and providing highly efficient use of each carriers time slots for receiving transmitting communication signals. Similarly, the signaling arrangement permits an efficient frame structure and a time slot assignment plan that does not require enhanced equipment at the mobile terminal.

Abstract: The number of surface defects in semiconductor materials having a volatile species, particulary group-III nitride-based semiconductor devices, are reduced by first implanting species atoms into the semiconductor sample to fill some of the surface layer species vacancies created by growth and device fabrication processes, and then rapid thermal annealing the sample to repair broken bonds and crystalline defects and to move implanted species atoms from interstitial to substitutional sites. An optional third step deposits a dummy layer on the sample surface prior to implantation, making possible an implantation profile that places a higher density of species atoms in the surface layer than is attainable without the dummy layer and to inhibit species atoms from leaving the sample during high-temperature processing steps that follow.

Abstract: A holographic optical filter separates broadband electromagnetic radiation into spectral components corresponding to different spectral regions and then images this radiation onto pixels of a display. It includes two layers of holographic optical elements that are sensitive to each of these spectral regions. The holographic optical elements generally transmit radiation outside of their bandpass but can diffract radiation falling within it. The filter is well suited for display applications and can be used in either a reflective or transmissive mode.

Abstract: A biocular display system (19) for generating a virtual image (30) of a visible display (20). A diffractive binary optical element (22) is used to create the virtual image (30). The binary optical element (22) contains magnifying power to increase the size of the virtual image (30). Also, the binary optical element (22) contains prismatic power to displace the virtual image (30) away from the display (20). Multiple displays (40), (42) may be viewed by employing a binary optical element (34) having multiple diffractive orders.

Abstract: An erasable optical memory is provided by an erasable bistable photoactive chromophore that is covalently bonded to a polymer microsphere. An azobenzene chromophore that is bonded to the microsphere by an oxygen or NH replacement of chlorine, or a CH double bond to N, is preferred. An array of such microspheres is encoded by applying radiation at a resonant wavelength to induce a conformational change in the chromophores for selected microspheres, and the encoded pattern is read out by detecting changes in either absorption or fluorescence.

Abstract: An imaging system that can tolerate high intensity optical beams without a reduction in the system's field-of-view, comprises an imager, a fiber array positioned at the image plane of the imager, a sensor array positioned at the output end of the fiber array, a panel display positioned in proximity of the fiber array and an image processor for electronically processing the information from the sensor array.

Abstract: A layer of sacrificial, chemically reactive material is formed as part of the fabrication process of an integrated circuit, and covers active circuitry to protect it from reaction with hydrogen. Integrated circuits and fabrication methods are provided by the present invention. The present invention is used to fabricate integrated circuits such as ferroelectric memories, and the like, using die or substrates containing one or more sacrificial layers of strontium bismuth niobate tantalate, for example. The sacrificial layers consume atmospheric hydrogen or other materials that otherwise would react with active circuitry of the integrated circuits and render them ineffective.

Abstract: A satellite television system that provides live television programming to passengers by integrating direct broadcast satellite services into an in-flight aircraft entertainment system. The system has an antenna disposed on the aircraft that is pointed at a plurality of satellites that are part of a direct broadcast satellite system. The antenna is controlled by an antenna controller and antenna interface unit that send control signals and process status signals to steer the antenna. The antenna is steered to lock it onto RF signals transmitted by the satellites. The antenna interface unit downconverts the received encoded RF signals to provide encoded left hand circularly polarized RF signals and right hand circularly polarized RF signals that contain different sets of television channels. The downconverted encoded RF signals are processed by a receiver to provide encoded video and audio signals of different television channels. The receiver does not decode or D/A convert the downconverted signals.