Abstract: A grid support system for tracker-mounted solar panel array for rooftop applications includes a base frame having a plurality of interconnected lateral members which define a generally planar area substantially parallel with the rooftop. The system also includes a set of support legs corresponding to each one of the tracker devices. The set of support legs are secured to the lateral members and extend upward and inward toward one another to a respective tracker mounting plate. The tracker mounting plate supports a tracker device and associated solar panel(s). A plurality of ballast trays are secured to the base frame and are adapted to hold a plurality of ballast weights for applying a downward force on the base frame to stabilize and resist movement of the base frame.

Abstract: An array of thyristor detector devices is provided having an epitaxial growth structure with complementary types of modulation doped quantum well interfaces located between a P+ layer and an N+ layer. The thyristor detector devices operate over successive cycles that each include a sequence of two distinct modes: a setup mode and a signal acquisition mode. During the setup mode, the n-type quantum well interface and/or the p-type quantum well interface is(are) substantially emptied of charge. During the signal acquisition mode, photocurrent is generated by the thyristor detector device in response to the absorption of incident electromagnetic radiation therein, which can induce the thyristor detector device to switch from an OFF state to an ON state. The OFF/ON state of the thyristor detector device produces an output digital electrical data that corresponds to the amount of incident radiation absorbed by the thyristor detector device during the signal acquisition mode of the current cycle.

Abstract: A solar photovoltaic module including a base member supporting an array of photocells as well as corresponding concentrating lenses and light guides. At least one opaque light shield defines cutouts corresponding to the light guides. The at least one opaque light shield is positioned above the base member and operates to block light incident thereon from reaching portions of the base member. The at least one light shield can be installed with a convex shape that directs condensation away from the cutouts and preferably functions as part of guide channels that guide condensation toward one or more vented hydrophilic members (e.g., sponges and the like), which are preferably disposed at one or both ends of the module.

Abstract: A solar photovoltaic module containing a housing that supports an array of photovoltaic cells and corresponding light guides. The housing includes a base member having a generally planar support surface and two side walls projecting from the support surface. Two side panels detachably connect to the side walls, and a top panel detachably connects to the side panels. The top panel includes a plurality of concentrating lenses that focus incident solar radiation into the inside of the housing towards the light guide. The light guides are disposed between the corresponding concentrating lenses and photovoltaic cells such that the concentrating lenses and light guides work together to direct light onto the photovoltaic cells. At least one retaining member interfaces to the light guides and applies a downward force that biases the respective light guides toward the corresponding photovoltaic cells.

Abstract: A method of fabricating a semiconductor device includes the steps of forming (or providing) a series of layers formed on a substrate, the layers including a first plurality of layers including an n-type ohmic contact layer, a p-type modulation doped quantum well structure, an n-type modulation doped quantum well structure, and a fourth plurality of layers including a p-type ohmic contact layer. Etch stop layers are used during etching operations when forming contacts to the n-type ohmic contact layer and contacts to the n-type modulation doped quantum well. Preferably, each such etch stop layer is made sufficiently thin to permit current tunneling therethrough during operation of optoelectronic/electronic devices realized from this structure (including heterojunction thyristor devices, n-channel HFET devices, p-channel HFET devices, p-type quantum-well-base bipolar transistor devices, and n-type quantum-well-base bipolar transistor devices).

Abstract: An optoelectronic circuit includes a resonant cavity formed on a substrate and into which is injected an input digital optical signal that encodes bits of information (each bit representing an OFF logic level or an ON logic level). A heterojunction thyristor device, formed in the resonant cavity, produces an output digital electrical signal corresponding to the input digital optical signal. A sampling clock defines sampling periods that overlap the bits (e.g., ON/OFF pulse durations) in the input digital optical signal. The sampling clock can be in the form of electrical pulses supplied to the n-channel injector terminal(s) and/or p-channel injector terminals of the heterojunction thyristor device. Alternatively, the sampling clock can be in the form of optical pulses that are part of the Optical IN signal that is resonantly absorbed by the device. The heterojunction thyristor device operates in an OFF state and an ON state.

Abstract: A method of fabricating a semiconductor device includes the steps of forming (or providing) a series of layers formed on a substrate, the layers including a first plurality of layers including an n-type ohmic contact layer, a p-type modulation doped quantum well structure, an n-type modulation doped quantum well structure, and a fourth plurality of layers including a p-type ohmic contact layer. Etch stop layers are used during etching operations when forming contacts to the n-type ohmic contact layer and contacts to the n-type modulation doped quantum well. Preferably, each such etch stop layer is made sufficiently thin to permit current tunneling therethrough during operation of optoelectronic/electronic devices realized from this structure (including heterojunction thyristor devices, n-channel HFET devices, p-channel HFET devices, p-type quantum-well-base bipolar transistor devices, and n-type quantum-well-base bipolar transistor devices).

Abstract: An integrated circuit is provided with a photonic device and a spot-size converter waveguide device integrated on a common substrate. The spot-size converter waveguide device provides for transformation between a larger spot-size and a smaller spot-size corresponding to the photonic device. The spot-size converter waveguide device includes at least one of a bottom mirror and top mirror, which provide highly-reflective lower and upper cladding, respectively, for vertical confinement of light propagating through the waveguide device. The top mirror overlies opposing sidewalls of the spot-converter waveguide device, which provide highly-reflective sidewall cladding for lateral confinement of light propagating through the waveguide device. Advantageously, the highly-reflective lower cladding provided by the bottom mirror limits optical loss of the waveguide device. Similarly, the highly-reflective upper cladding and sidewall cladding provided by the top mirror limits optical loss of the waveguide device.

Abstract: An improved imaging array (and corresponding method of operation) includes a plurality of heterojunction thyristor-based pixel elements disposed within resonant cavities formed on a substrate. Each thyristor-based pixel element includes complementary n-type and p-type modulation doped quantum well interfaces that are spaced apart from one another. Incident radiation within a predetermined wavelength resonates within the cavity of a given pixel element for absorption therein that causes charge accumulation. The accumulated charge is related to the intensity of the incident radiation. The heterojunction-thyristor-based pixel element is suitable for many imaging applications, including CCD-based imaging arrays and active-pixel imaging arrays.

Abstract: Interference caused by the propagation of a transmit signal transmitted from a transmit antenna to a receive antenna is effectively cancelled by an improved signal cancellation system. The system includes an interference cancellation signal generator that generates a time-delayed and amplitude-reduced representation of said transmit signal. A summing stage is operably coupled to the interference cancellation signal generator and the receive antenna. The summing stage subtracts the time-delayed and amplitude-reduced representation of the transmit signal from a receive signal to substantially cancel the interference. The interference cancellation signal generator preferably includes a novel programmable optical delay line that introduces a variable amount of optical delay to an optical signal derived from said transmit signal in addition to a thyristor-based sigma delta modulator that converts samples of the transmit signal to into a digital signal in the optical domain.

Abstract: A thyristor and family of high speed transistors and optoelectronic devices are obtained on a monolithic substrate (149) with an epitaxial layer structure comprised of two modulation doped transistor structures inverted with respect to each other. The transistor structures are obtained by adding planar doping to the Pseudomorphic High Electron Mobility Transistor (PHEMT) structure. For one transistor, two sheets of planar doping of the same polarity separated by a lightly doped layer are added which are opposite to the modulation doping of the PHEMT. The combination is separated from the PHEMT modulation doping by undoped material. The charge sheets are thin and highly doped. The top charge sheet (168) achieves low gate contact resistance and the bottom charge sheet (153) defines the capacitance of the field-effect transistor (FET) with respect to the modulation doping layer of the PHEMT. For the other transistor, only one additional sheet is added.

Abstract: An optoelectronic circuit includes a resonant cavity formed on a substrate and into which is injected an input digital optical signal that encodes bits of information (each bit representing an OFF logic level or an ON logic level). A heterojunction thyristor device, formed in the resonant cavity, produces an output digital electrical signal corresponding to the input digital optical signal. A sampling clock defines sampling periods that overlap the bits (e.g., ON/OFF pulse durations) in the input digital optical signal. The sampling clock can be in the form of electrical pulses supplied to the n-channel injector terminal(s) and/or p-channel injector terminals of the heterojunction thyristor device. Alternatively, the sampling clock can be in the form of optical pulses that are part of the Optical IN signal that is resonantly absorbed by the device. The heterojunction thyristor device operates in an OFF state and an ON state.

Abstract: An integrated circuit (and optical transceiver module) includes an optoelectronic thyristor device formed within a resonant cavity on a substrate, and circuitry integrally formed on the substrate that dynamically switches the thyristor between a transmit mode configuration and a receive mode configuration. In the transmit mode configuration, the thyristor is modulated between a non-lasing state and a lasing state in accordance with an input digital electrical signal. In the receive mode configuration, the thyristor device is modulated between a non-lasing OFF state and a non-lasing ON state in accordance with an input digital optical signal that is injected into the resonant cavity to thereby produce an output digital electrical data signal that corresponds to the input digital optical signal. The integrated circuit (and optical transceiver module) can be used in optical fiber applications as well as free-space applications.

Abstract: An optoelectronic pulse generator is provided that includes a thyristor detector/emitter device having an input port and an output port. The thyristor detector/emitter device is adapted to detect an input optical pulse supplied to the input port and to produce an output optical pulse (via laser emission) and an output electrical pulse in response to the detected input optical pulse. The output optical pulse is output via the output port. An optical feedback path is operably coupled between the output port and the input port of the thyristor detector/emitter device. The optical feedback path supplies a portion of the output optical pulse produced by the thyristor detector/emitter device to the input port, thereby causing the thyristor detector/emitter device to produce a sequence of output optical pulses and a corresponding sequence of output electrical pulses.

Abstract: A semiconductor device includes a series of layers formed on a substrate, the layers including a first plurality of layers including an n-type ohmic contact layer, a p-type modulation doped quantum well structure, an n-type modulation doped quantum well structure, and a fourth plurality of layers including a p-type ohmic contact layer. Etch stop layers are used to form contacts to the n-type ohmic contact layer and contacts to the n-type modulation doped quantum well structure. Thin capping layers are also provided to protect certain layers from oxidation. Preferably, each such etch stop layer is made sufficiently thin to permit current tunneling therethrough during operation of optoelectronic/electronic devices realized from this structure (including heterojunction thyristor devices, n-channel HFET devices, p-channel HFET devices, p-type quantum-well-base bipolar transistor devices, and n-type quantum-well-base bipolar transistor devices).

Abstract: A method of fabricating a semiconductor device includes the steps of forming (or providing) a series of layers formed on a substrate, the layers including a first plurality of layers including an n-type ohmic contact layer, a p-type modulation doped quantum well structure, an n-type modulation doped quantum well structure, and a fourth plurality of layers including a p-type ohmic contact layer. Etch stop layers are used during etching operations when forming contacts to the n-type ohmic contact layer and contacts to the n-type modulation doped quantum well. Preferably, each such etch stop layer is made sufficiently thin to permit current tunneling therethrough during operation of optoelectronic/electronic devices realized from this structure (including heterojunction thyristor devices, n-channel HFET devices, p-channel HFET devices, p-type quantum-well-base bipolar transistor devices, and n-type quantum-well-base bipolar transistor devices).

Abstract: A photonic digital-to-analog converter employing a plurality of heterojunction thyristor devices that are configured to convert a digital word encoded by a parallel digital optical signal (e.g., a plurality of synchronous optical bits) to an output analog electrical signal whose magnitude corresponds to the digital word. Each heterojunction thyristor device is configured to convert an optical bit in the digital word to a corresponding digital electrical signal. The voltage levels (e.g., magnitudes) of the ON state of the digital electrical signals produced by the heterojunction thyristor devices may be supplied by voltage divider networks coupled between the cathode terminal of the devices and ground potential or voltage reference sources coupled to the input terminals of the heterojunction thyristor devices. In this manner, electrical signals whose magnitude corresponds to contribution of each optical bit in the digital word are produced.

Abstract: An optoelectronic integrated circuit comprises a substrate, a multilayer structure formed on the substrate, and an array of thyristor devices and corresponding resonant cavities formed in the multilayer structure. The resonant cavities, which are adapted to process different wavelengths of light, are formed by selectively removing portions of said multilayer structure to provide said resonant cavities with different vertical dimensions that correspond to the different wavelengths. Preferably, that portion of the multilayer structure that is selectively removed to provide the multiple wavelengths includes a periodic substructure formed by repeating pairs of an undoped spacer layer and an undoped etch stop layer. The multilayer structure may be formed from group III-V materials. In this case, the undoped spacer layer and undoped etch stop layer of the periodic substructure preferably comprises undoped GaAs and undoped AlAs, respectively.

Abstract: An optoelectronic integrated circuit includes a resonant cavity formed on a substrate. A heterojunction thyristor device is formed in the resonant cavity and operates to detect an input optical pulse (or input electrical pulse) and produce an output optical pulse via laser emission in response to the detected input pulse. The heterojunction thyristor device includes a channel region that is coupled to a current source that draws current from the channel region. Time delay between the input pulse and output optical pulse may be varied by configuring the current source to draw constant current from the channel region and modulating the intensity of the input pulse, or by varying the amount of current drawn from the channel region by the current source. The heterojunction thyristor device may be formed from a multilayer structure of group III-V materials, or from a multilayer structure of strained silicon materials.

Abstract: A serial photonic digital-to-analog converter employs a heterojunction thyristor device configured for optically-controlled sampling/switching to convert a digital word encoded by a serial digital optical data signal (e.g., serial optical bit stream) into a corresponding analog electrical signal. A voltage reference is operably coupled to the electrical input terminal of the heterojunction thyristor device. The voltage reference cooperates with the heterojunction thyristor device to sequentially generate at its electrical output terminal a voltage signal representing contribution of each bit of the digital word encoded in the serial digital optical data signal. A summing network is operably coupled to the electrical output terminal of the device. The summing network sequentially sums contribution of the voltage signal over the sequence of bits to produce an analog electrical signal corresponding to the digital word for output therefrom.