Abstract: A system includes a Mobile User Objective System (MUOS) geostationary earth orbit (GEO)-based communication satellites (ComSat) to provide a persistent and on-demand communication links between multiple LEO space vehicles, their associated air and/or ground users and operations centers. The system further includes one or more LEO space vehicles that can communicate with the GEO-based MUOS ComSats using UHF communication links. Each of the LEO space vehicles includes radio circuitry to enable communicating over an ultra-high frequency (UHF) band used by the MUOS GEO communication link in compliance with the MUOS Wideband Code-Division Multiple-Access WCDMA waveform standard or other user defendable waveforms.

Abstract: A compact photonic radio frequency receiver system includes a laser source that is configured to generate laser light Radio frequency (RF) and local oscillator (LO) input ports may receive RF and LO signals, respectively. One or more miniature lithium niobate waveguide phase modulators may be coupled to the laser source to receive the RF and LO signals and to modulate the laser light with the RF and LO signals in a first and a second path, and to generate phase-modulated laser lights including an RF-modulated light signal and an LO-modulated light signal. A first and a second miniature filter may be coupled to the miniature lithium niobate waveguide to separate a desired spectral band in the phase-modulated laser light of the first path and to facilitate wavelength locking of the laser light of the second path. An optical combiner may combine output laser lights of the first and second filters.

Abstract: High-power electronic components generate significant amounts of heat that must be removed in the course of normal device operations. Certain types of electronic components, such as some monolithic microwave integrated circuits and LEDs, can contain materials that are difficult to effectively bond to a heat gink in order to establish a thermal interface between the two. Device assemblies can include a heat-generating electronic component in thermal communication with a metallic heat sink via a metallic thermal interface layer. The metallic thermal interface layer is disposed between the heat-generating electronic component and the metallic heat sink. The metallic thermal interface layer is formed from a composition including a plurality of metal nanoparticles that are at least partially fused together with one another.

Abstract: A compact photonic radio frequency receiver system includes a laser source that is configured to generate laser light Radio frequency (RF) and local oscillator (LO) input ports may receive RF and LO signals, respectively. One or more miniature lithium niobate waveguide phase modulators may be coupled to the laser source to receive the RF and LO signals and to modulate the laser light with the RF and LO signals in a first and a second path, and to generate phase-modulated laser lights including an RF-modulated light signal and an LO-modulated light signal. A first and a second miniature filter may be coupled to the miniature lithium niobate waveguide to separate a desired spectral band in the phase-modulated laser light of the first path and to facilitate wavelength locking of the laser light of the second path.

Abstract: High-power electronic components generate significant amounts of heat that must be removed in the course of normal device operations. Certain types of electronic components, such as some monolithic microwave integrated circuits and LEDs, can contain materials that are difficult to effectively bond to a heat gink in order to establish a thermal interface between the two. Device assemblies can include a heat-generating electronic component in thermal communication with a metallic heat sink via a metallic thermal interface layer. The metallic thermal interface layer is disposed between the heat-generating electronic component and the metallic heat sink. The metallic thermal interface layer is formed from a composition including a plurality of metal nanoparticles that are at least partially fused together with one another.

Abstract: A method and apparatus for transferring information of an optical information-bearing signal from a first wavelength to a second wavelength. The method is implemented in an all-optical wavelength converter circuit which includes a laser diode in communication with a polarization controller. An information-bearing signal having a first wavelength is input to the circuit. A polarization controller adjusts the polarization of the information-bearing signal. The laser diode receives the polarization-adjusted information-bearing signal and generates a converted information-bearing signal by transferring the information of the polarization-adjusted information-bearing signal from the first wavelength to the second wavelength. The polarization controller receives the converted information-bearing signal from the laser diode, and polarizes the converted information-bearing signal.

Abstract: A temperature controlled arrangement is provided for housing an optical component such as a laser diode that may be employed in a CATV system. The arrangement includes a package having an enclosure through which a plurality of electrical connections extend. At least one optical component is located in the enclosure and electrically connected to at least one of the electrical connections. A first thermoelectric cooler is also located in the enclosure and in thermal conduction with the optical component. A temperature sensor is located in the enclosure and electrically connected to at least one of the electrical connections. A second thermoelectric cooler, which is located external to the enclosure, is in thermal conduction with the enclosure.

Abstract: A fiber optic link is provided that is receptive of an AM RF input signal, includes an analog comparator for comparing the input signal with a triangle waveform to convert the input signal to a PWM signal. The PWM signal is converted into an optical signal, and transmitted over a fiber optic cable to an optical receiver. The optical receiver converts the optical signal back into a PWM signal, which is amplified via a Class D amplifier. The amplified PWM signal is passed through a low pass filter for converting it into an AM RF output signal having a predetermined power level, the output signal corresponding to the AM RF input signal.

Abstract: A method and apparatus for transferring information of an optical information-bearing signal from a first wavelength to a second wavelength. The method is implemented in an all-optical wavelength converter circuit which includes a laser diode in communication with a polarization controller. An information-bearing signal having a first wavelength is input to the circuit. A polarization controller adjusts the polarization of the information-bearing signal. The laser diode receives the polarization-adjusted information-bearing signal and generates a converted information-bearing signal by transferring the information of the polarization-adjusted information-bearing signal from the first wavelength to the second wavelength. The polarization controller receives the converted information-bearing signal from the laser diode, and polarizes the converted information-bearing signal.

Abstract: A temperature controlled arrangement is provided for housing an optical component such as a laser diode that may be employed in a CATV system. The arrangement includes a package having an enclosure through which a plurality of electrical connections extend. At least one optical component is located in the enclosure and electrically connected to at least one of the electrical connections. A first thermoelectric cooler is also located in the enclosure and in thermal conduction with the optical component. A temperature sensor is located in the enclosure and electrically connected to at least one of the electrical connections. A second thermoelectric cooler, which is located external to the enclosure, is in thermal conduction with the enclosure.

Abstract: A transmitter in a digital return link for use in an HFC network includes an analog to digital converter for digitizing a broadband analog RF input. The A/D converter has a parallel bit stream output. A serializer converts the parallel bit stream from the converter to a serial bit stream. An electroabsorption modulated laser converts the serial bit stream to an optical serial bit stream for transmission over the HFC network.

Abstract: An optical detector for determining the wavelength of an optical signal iudes a semiconductor material in the path of the optical signal having a bandgap less than the optical signal. A conductive layer is positioned on the semiconductor material and a plurality of conductive pads are also positioned on the semiconductor material to delineate individual photodetectors. The pads have a common node established by the conductive layer. The optical detector produces a plurality of photocurrents between the pads and the conductive layer in response to the optical signal which photocurrents can be measured and compared to determine the wavelength of the optical signal. A system for determining the wavelength of the optical signal includes a plurality of optical detectors numbered 1 to n positioned sequentially in the path of the optical signal. The detectors produce photocurrents which are converted into digital signals. A microprocessor receives the digital signals and determines a ratio therebetween.

Abstract: An FET or MESFET having a semiconductor optically transparent gate. A substrate having a doped channel placed thereon together with a source and a drain with a semiconductor gate formed therebetween may be manufactured using conventional semiconductor manufacturing techniques. The optically transparent highly doped semiconductor gate forms an n+-n junction with the n-type doped channel. This junction is modulated or changed by an optical signal causing a photovoltaic effect that reduces the barrier potential at the n+-n junction resulting in a depletion of the accumulation region. This results in increased flow of current in the doped channel. The transparent highly doped semiconductor gate increases performance of the FET or MESFET optical detector. This is an improvement over conventional metal semiconductor field-effect transistor (MESFET) technology, and can be applied to microwave monolithic integrated circuits (MMIC).

Abstract: An optical detector comprised of a MESFET having a larger than usual separation between its source and drain electrodes and a channel between the source and drain electrodes doped with carriers having a density of at least 10.sup.18 /cm.sup.3 whereby variation in the voltage of the gate electrode changes the optical gain.

Abstract: A dual-gate self-oscillating mixer FET that is injection-locked from a remote LO frequency source. The dual-gate FET having a feedback circuit connected between the first gate port and the drain port that is tuned so that the FET can oscillate within a frequency range including a predetermined LO frequency. The FET having a remote synchronization circuit electrically connected to the FET first gate port to inject the predetermined LO frequency therein and lock the FET oscillation to that LO. Accordingly, the dual-gate FET mixes RF energy input to the second gate port with the locked LO injected in the first gate port and outputs the desired intermediate frequency through the drain port.

Abstract: A tapered waveguide for transmitting optical signals from a signal source to an optical fiber is fabricated by irradiating a layer of prepolymer resin on a substrate with a converging beam of ultraviolet light, whereby the irradiated resin polymerizes into a clear, hard polymer and the resin that has not been irradiated remains in its resinous state. The unpolymerized resin is removed with an organic solvent. The variation in width of the waveguide is achieved by varying the distance between the source of the converging beam of ultraviolet light, thereby varying the diameter of the spot that is being irradiated, while simultaneously moving the source of ultraviolet light parallel to the axis of the waveguide. Variation in thickness of the waveguide is achieved by sloping the substrate.

Abstract: The coupling of optical signals to the active region of a FET having a wide source to drain spacing via an optical fiber and material having an index of refraction matching that of the fiber or the FET so as to increase the locking range when the FET is part of an oscillator circuit or to increase the change in the electrical gain of the FET caused by a change in the optical energy if the FET is an amplifier.

Abstract: An optically controlled resonant tunnel diode oscillator assembly having a esonant tunnel diode (RTD) which, when voltage biased, oscillates at a free running frequency; an optical signal delivery system, such as a light intensity modulator connected to optical fibers; and other oscillator circuitry which one skilled in the art could readily adapt to the concepts of the present invention. In operation, the free running oscillation of the RTD can be frequency modulated or can be intensity locked to the intensity modulated optical signal delivered via the optical signal delivery system.

Abstract: A method and system for steering an antenna beam are provided. A light source emits light wherein at least one parameter of the emitted light is modulated. Modulated light is received by an optical detector and an analog control signal is provided by the optical detector in response to the modulated parameter. The control signal is applied to an analog-to-digital converter to convert the signal from analog to digital. The digital converter output signal is applied to a digital phase shifter for controlling the phase shift of the phase shifter and thereby steering an antenna beam according to the modulated parameter. The modulated parameter may be, for example, the intensity of the emitted light or the frequency of the emitted light. A plurality of converters and phase shifters may be provided for steering of phased array antennas.

Abstract: An optical controlled attenuator circuit for controlling a microwave varie attenuator. The optical controlled attenuator circuit includes, a light source, a control connected to the light source, an optic fiber having an end coupled to the light source, a field effect transistor coupled to a second end of the optic fiber, a first inverting amplifier coupled to the field effect transistor, a second non-inverting amplifier coupled to the first amplifier means, a third non-inverting amplifier coupled to the second amplifier, a fourth inverting amplifier means also coupled to the second amplifier, and a microwave variable attenuator having first and second inputs respectively coupled to the fourth inverting amplifier and to the third non-inverting amplifier means and having an RF input and an RF output.