Abstract: A radio frequency (RF) to optical converter for RF imaging, wherein the converter comprises an array of RF antenna pixels adapted to receive RF signals, wherein the RF antenna pixels are adapted to facilitate RF resonance of the received RF signals; a photonic band gap (PBG) layer connected to the array of RF antenna pixels, the PBG layer comprising at least two materials, arranged in a photonic crystal (PC), wherein at least one of the materials comprises an electro-optic (EO) material, wherein the EO material is adapted to use the RF resonant signals to produce changes in optical properties of the EO material, and wherein the PC is adapted to use changes in optical properties of the EO material to produce enhanced changes in optical properties of the PBG layer; and an RF ground plane connected to the PBG layer.

Abstract: A reconfigurable photonic band gap device having a substrate and a crystal membrane with a lattice structure having its ends attached to a substrate so that a midportion of the lattice membrane is spaced upwardly from the substrate and forms a chamber therebetween. A bridge is disposed in the chamber between and separated from both the lattice membrane midportion and the substrate. At least one post is attached to the bridge and aligned with at least one hole in the lattice so that movement of the bridge relative to the lattice varies the degree of insertion of the post relative to its associated hole to vary the photonic band gap behavior of the device.

Abstract: An injection locked dual opto-electronic oscillator having a master oscillator which generates a high Q RF output signal with a plurality of harmonic signals within a predetermined pass band. A slave oscillator has a modulation input coupled to the output signal from the master oscillator as well as an output signal. The slave oscillator has a cavity length selected to produce a single mode operation within the pass band. An electronic phase shifter in the slave oscillator is adjustable to produce constructive interference at a single harmonic of the output signal from the master oscillator and destructive interference of all other harmonics within the pass band and to bring the slave oscillator into injection locked condition with the master oscillator. Therefore the slave OEO is used as a filter for the spurious radiation generated by the master OEO and at the same time preserves the high Q of the RF carrier signal from the master OEO.

Abstract: A true time delay system for optical control of a phased array antenna includes a first time delay unit having a pair of parallel end walls having mirrored surfaces facing each other in a zigzag pattern, and an intermediate wall which is substantially parallel to the end walls and has mirrored surfaces on both sides which match the end walls. The intermediate wall also has matching openings in the mirrored surfaces to permit light to pass through the intermediate wall. A displacement unit displaces the intermediate wall relative to the end walls to change the distance that a series of input light beams travels, creating a true time delay between each two consecutive light beams in a first dimension. A second time delay unit receives the output of the first time delay unit, provides a time delay between each two consecutive light beams in a second dimension and outputs light beams having a sequence of time delay in both the first and second dimensions.

Abstract: An optical signal processor is implemented as a monolithically integrated semiconductor structure having optical waveguide devices forming beam splitters, optical amplifiers and optical phase shifters. The monolithic structure photonically controls a phased-array microwave antenna. Phase-locked master and slave lasers generate orthogonal light beams having a difference frequency that corresponds to the microwave carrier frequency of the phased-array antenna. The lasers feed the signal processor, which performs beam splitting, optical amplifying and phase shifting functions. A polarizer and an array of diode detectors convert optical output signals from the signal processor into microwave signals that feed the phased-array antenna. The optical waveguides of the signal processor are fabricated in a single selective epitaxial growth step on a semiconductor substrate.

Abstract: Opto-electronic integrated waveguide devices are provided using a tilted valence band quantum well semiconductor double heterostructure with one growth of the same waveguide material, that operate simply by their normal operating forward bias for active waveguides with optical gain and operating in a reverse or no bias for active waveguide without optical gain or passive waveguides. The optical waveguides comprise a substrate, a bottom cladding layer, a core layer having a quantum well optical waveguiding double heterostructure and a top cladding layer. The quantum well optical waveguiding double heterostructure includes an InGaPAs first barrier layer atop the bottom cladding layer, a quantum well layer constructed of InxGa1.sub.-x-y Al.sub.y As is stacked on top of the first barrier layer which is graded from one side to the other forming a linearly increasing quantum well energy bandgap and an In.sub..52 AlGaAs second barrier layer is stacked on top of said quantum well core layer.

Abstract: An optical signal processor is implemented as a monolithically integrated semiconductor structure having optical waveguide devices forming beam splitters, optical amplifiers and optical phase shifters. The monolithic structure photonically controls a phased-array microwave antenna. Phase-locked master and slave lasers generate orthogonal light beams having a difference frequency that corresponds to the microwave carrier frequency of the phased-array antenna. The lasers feed the signal processor, which performs beam splitting, optical amplifying and phase shifting functions. A polarizer and an array of diode detectors convert optical output signals from the signal processor into microwave signals that feed the phased-array antenna. The optical waveguides of the signal processor are fabricated in a single selective epitaxial growth step on a semiconductor substrate.

Abstract: An optical signal processor is implemented as a monolithically integrated semiconductor structure having optical waveguide devices forming beam splitters, optical amplifiers and optical phase shifters. The monolithic structure photonically controls a phased-array microwave antenna. Phase-locked master and slave lasers generate orthogonal light beams having a difference frequency that corresponds to the microwave carrier frequency of the phased-array antenna. The lasers feed the signal processor, which performs beam splitting, optical amplifying and phase shifting functions. A polarizer and an array of diode detectors convert optical output signals from the signal processor into microwave signals that feed the phased-array antenna. The optical waveguides of the signal processor are fabricated in a single selective epitaxial growth step on a semiconductor substrate.

Abstract: The dielectric constant and the optical properties of a semiconductor device are changed by tuning the electron density in modulation doped quantum wells. The quantum wells are formed in an "i" region of a p-i-n structure having, in sequence, a 150 .ANG. wide GaAs quantum well, a wider Al.sub.x Ga.sub.1-x As barrier with a central silicon doped section and an undoped AlGaAs barrier with a slightly higher barrier height to prevent transfer of carriers to the next well. When a reverse bias is applied, more D centers are tuned below the Fermi level so that they can trap electrons from the wells, thereby reducing electron density and changing the optical properties of the material.

Abstract: An opto-electronic semiconductor device including a variable strained layered quantum well structure having at least two superimposed heavy- and light-hole triangular bottom valance band quantum wells with mutually opposite slopes. Upon the application of a bias potential across a thickness dimension of the quantum wells, an electric field is generated therethrough which produces an interchange of the confined energy levels of heavy-holes and light-holes in the quantum wells which causes a change in the transmission characteristics of light passing through the device as a result of the heavy- and light-hole energy bands having different light absorption anisotropy.