Abstract: An electro-optic interconnect for use with optical signals and a probe beam is disclosed. A plurality of first optoelectronic detectors responds to an optical signal and develops a plurality of first electrical signals. A probe laser generates the probe beam. Means are responsive to the plurality of first electrical signals and changes a characteristic of the optical probe beam. A second optoelectronic detector responds to the changed characteristic and develops an output electrical signal representative of the optical signals. Alternatively, the second optoelectronic detector can be eliminated and direct optical signal processing can be implemented. In another aspect, a time compensation network serves to synchronize the probe and the signal beams. The electro-optic interconnect can be configured to add and subtract the optical signals.

Abstract: An optoelectronic communication system for use with an optical signal that passes through a turbulent environment is disclosed. The communication system comprises an optical transmitter for transmitting an optical signal, and an optoelectronic receiver. The optoelectronic receiver comprises a reflector for collecting the optical signal and for propagating a plurality of portions of it. A plurality of first optoelectronic detectors responds to a selected portion of the optical signal and each develops a plurality of first electrical signals. A probe laser generates an optical probe beam. Means are responsive to the plurality of first electrical signals and changes a characteristic of the optical probe beam corresponding to the information. A second optoelectronic detector responds to the changed characteristic and develops an output electrical signal representative of the information contained in the received optical signal.

Abstract: A time compensation architecture for use with a plurality of optical signals is disclosed. It comprises means for receiving the plurality of optical signals, optical means for selectively delaying the propagation of each of the plurality of optical signals, and means for outputting the time delayed optical signals. The delay may be achieved by changing the indices of refraction or the material lengths of the elements and can either be an active or a passive compensation technique.

Abstract: An optical device for use with an optical input beam comprising an optical thresholding device positioned along an optical path defined by the propagation direction of the optical input beam. If the combined intensity of the optical input beam and a control beam exceeds a threshold level, the optical beam passes through the thresholding device. Preferably, the optical thresholding device is a saturable absorber. When the device is configured as an optical comparator, the intensity of the optical input beam exceeds the threshold level and the thresholding device saturates and turns transparent so that the control beam passes through the thresholding device as an optical indicator beam. When the device is configured as an optical signal attenuator and the intensity of the optical input signal is negligible compared to that of the control beam, the combined intensity of the beams does not saturate the thresholding device.

Abstract: An optical interconnect for use with a probe beam and optical signals is disclosed. The interconnect comprises an optical waveguide for propagating the probe beam, an optical transcription material that changes a characteristic of the probe beam at locations where the optical signals interact with the probe beam. A signal processor develops an output signal from the changed characteristic representative of the information contained in the optical signals. The optical signals may be amplitude or phase modulated or polarized. The interconnect can be configured to add and subtract the optical signals.

Abstract: A broadcast optical communication system is disclosed. It comprises an optical waveguide having a plurality of gratings. A first grating is disposed at a first node and couples light impinging normally into the waveguide, propagates coupled light bi-directionally through the waveguide and emits a portion of the coupled light at a second grating in a direction normal thereto. An optical source is disposed proximate the first node for transmitting light normally to the first grating and an optical detector is disposed proximate the second node for detecting the normally emitted light. In another embodiment multiple optical waveguides and source-detector pairs are employed in a parallel data architecture to provide multiple channel broadcast communication.

Abstract: An optical communication system uses a radio frequency (RF) signal for communicating an analog communication signal. It comprises an optical transmitter and receiver. The optical transmitter comprises means for generating a first reference light beam, and means responsive to the analog communication signal to produce a communication light beam having phase modulation corresponding to the analog communication signal.

Abstract: An apparatus and a method for stabilizing an optical interferometer using two optical signals that differ in wavelength by a factor of two is disclosed. The optical interferometer has an optical path length that is tunable. It develops a first interference pattern when the original optical signal is present and the optical path length is a prescribed value. When a second optical signal that has a wavelength that is twice or one-half of the original is dithered and a path length adjustment drive signal is present the interferometer develops a second interference pattern when the optical path length is the prescribed value. An optoelectronic detector is responsive to the second optical interference pattern and develops an electronic feedback signal when the second interference pattern is not present.

Abstract: An optical communication system, using a radio frequency (RF) signal for communicating an analog communication signal, includes an optical transmitter and an optical receiver. The optical transmitter generates a reference light beam, generates a phase modulated communication light beam by phase modulating the reference light beam with the analog communication signal, polarizes a portion of the reference light beam and combines the polarized reference light beam and the phase modulated communication light beam.

Abstract: A solar cell comprises a superstrate formed from a material that is transparent to light, a first layer formed of delta doped silicon, a plurality of layers formed from semiconductor materials, each characterized by multi-quantum wells and multiple band gaps, a first semiconductor layer having a band gap energy state that is the smallest, the last semiconductor layer having-a band gap that is the largest, and the intermediate semiconductor layers having band gaps transitioning from the smallest to the largest, a second layer overlying the semiconductor layers and formed of delta doped silicon, an n-cap layer formed on the second delta doped layer, and a metal layer formed on the n-cap layer and serving to reflect light into the semiconductor.

Abstract: A detector for detecting infrared photons is disclosed. It comprises an anode, a cathode including a plurality of nanotubes formed from carbon and means for electrically connecting the nanotubes, and bias circuitry for applying an electric field between the anode and the cathode such that when infrared photons are absorbed by the nanotubes, photoelectrons are created. A gate electrode is disposed between the anode and the cathode and controls the passage of the photoelectrons passing therethrough. A pulse height analyzer separates photoelectrons from electrons created by field emission from the nanotubes and serves to measure the photoelectrons.

Abstract: An apparatus using an optical signal for actively tuning an optical interferometer without introducing any dither in its optical path length.

Abstract: A high average power fiber-laser system comprises a master oscillator for generating a primary laser signal; a beam splitter array for splitting the primary laser signal into N secondary laser signals; an optical frequency shifter for shifting the frequency of the primary laser signal; a phase modulator array for providing phase compensation of the N secondary laser signals; N single-mode dual clad fiber amplifiers for amplifying the N secondary laser signals and generating an output beam; a beam sampler for sampling the wavefront of the output beam, defining an array of sampled signals; means responsive to the array of sampled signals for interferometrically combining the array of said sampled signals and the shifted primary laser signal into an array of heterodyne optical signals, each having a phase that corresponds to the state of phase of the array of sampled signals; and means responsive to the array of heterodyne optical signals for providing a plurality of feedback signals to the phase modulator array

Abstract: An optical device for use with an optical input beam comprises and optical thresholding device having a predetermined threshold level, and is positioned along an optical path defined by the propagation direction of the optical input beam. A source generates a control beam through the optical thresholding device, wherein if the combined intensity of the optical input beam and the control beam is large enough to exceed the threshold level of the thresholding device, the optical beam passes through he thresholding device. The thresholding device attenuates the optical beam as it passes therethrough. In a preferred embodiment, the optical thresholding device is a saturable absorber.

Abstract: A lanthanum aluminate (LaAlO3) substrate on which thin films of layered perovskite copper oxide superconductors are formed. Lanthanum aluminate, with a pseudo-cubic perovskite crystal structure, has a crystal structure and lattice constant that closely match the crystal structures and lattice constants of the layered perovskite superconductors. Therefore, it promotes epitaxial film growth of the superconductors, with the crystals being oriented in the proper direction for good superconductive electrical properties, such as a high critical current density. In addition, LaAlO3 has good high frequency properties, such as a low loss tangent and low dielectric constant at superconductive temperatures. Finally, lanthanum aluminate does not significantly interact with the superconductors. Lanthanum aluminate can also used to form thin insulating films between the superconductor layers, which allows for the fabrication of a wide variety of superconductor circuit elements.

Abstract: A wavelength division multiplexed optical communication system comprises an optical waveguide having a plurality of gratings, each defining a node. A first grating is disposed at a first node couples impinging light at a plurality of preselected wavelengths into the waveguide. The coupled light propagates through the waveguide and is emitted at a second and at a third grating in directions corresponding to each of the preselected wavelengths. A plurality of optical sources is arranged proximate the first node, each source transmitting an optical signal at a preselected wavelength that differs from that transmitted by the other sources and arranged to transmit light to the first grating. Optical detectors are disposed proximate the second and the third nodes, and positioned in directions corresponding to the emitted light. Thus each detector detects one of the preselected wavelengths. This constitutes a broadcast type of communication system.

Abstract: An antenna system that includes one or more antenna feed horns (30), where each feed horn (30) includes a plurality of micro-mechanical devices (38) positioned around the aperture (32) of the feed horn (30). The micro-mechanical devices (38) are linear motion devices that can be activated to extend a conductive surface (40) beyond the end of the feed horn (30). By selectively actuating groups of the micro-mechanical devices (38) to extend the conductive surfaces (40), the end of the feed horn (30) can be changed to provide different asymmetrical configurations, causing the beam direction to change accordingly. The micro-mechanical devices (38) can be any suitable mechanical device, such as MEMS devices or carbon nanotube artificial muscles.

Abstract: An adaptive transceiver architecture which reallocates communications resources in real time based on the amount of bandwidth being used in communications channels in the system. The transceiver receives communications signals from a plurality of communications beam spots. Each communications beam spot has a predefined bandwidth divided into non-overlapping subbands. The transceiver further comprises a plurality of front end signal conditioners for receiving communications signals from an equal plurality of communications beam spots. A predetermined number of the conditioned signals are then combined by an interconnect. The interconnect receives composite signals from the front end signal conditioners, and it combines at least first and second communications signals from first and second respective composite signals to form an output processing signal.

Abstract: A technique for measuring distortion in a structure of interest, such as a spacecraft antenna reflector (18), and optionally compensating for the distortion. A first set of targets (22) on the structure (18) is scanned by an attitude transfer system (24) to measure the angular location and range of each target relative to a reference point on another structure (12) having a frame of reference. The orientation of the structure of interest is them determined from the measured locations of the targets. A second set of targets (60 or 82) on the structure of interest is scanned by a figure sensing module (26) located at a reference point on the structure itself. From measured angular locations and ranges of the second set of targets, any shape distortion in the structure of interest can be determined, and distortion may be corrected with the use of actuators (98).

Abstract: An interconnect, having some length, that reliably connects two conductors separated by the length of the interconnect when the connection is made but in which one length if unstressed would change relative to the other in operation. The interconnect comprises a base element an intermediate element and a top element. Each element is rectangular and formed of a conducting material and has opposed ends. The elements are arranged in a generally Z-shape with the base element having one end adapted to be connected to one conductor. The top element has one end adapted to be connected to another conductor and the intermediate element has its ends disposed against the other end of the base and the top element. Brazes mechanically and electrically interconnect the intermediate element to the base and the top elements proximate the corresponding ends of the elements.