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: A semiconductor waveguide modulator that is polarization insensitive/independent at bias variations for any chosen wavelength. The modulator of the present invention employs a novel type of strained semiconductor quantum well (QW) structure that exhibits bias independent, heavy-hole and light hole degeneracy. This effect is achieved by inserting one or two thin layers of highly tensile, strained materials in a specific position within the QW. By adjusting the thickness and the position of the highly tensile strained layers, the quantum confined Stark effect (QCSE) for the heavy hole and light hole can be engineered separately to control the bias dependent polarization properties. The present invention has applications, for example, in optoelectronic devices in the areas of telecommunications, optical signal processing, scanning and displays.

Abstract: A vertical cavity surface emitting laser is formed by eutectically bonding a laser cavity, defined by an active layer disposed between first and second, stacked mirror assemblies, to a host substrate which has a predetermined anisotropic coefficient of thermal expansion. During the forming process, a uniaxial strain is induced within the laser cavity. With this arrangement, large arrays of vertical cavity surface emitting lasers can be formed with predetermined polarization states that are based on the selected anisotropic host 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: An MQW is fabricated such that at a particular level of purely mechanical ress/strain the optical properties of the MQW are altered by breaking the heavy and light hole degeneracy (splitting of the heavy and light holes in the valence band) of the MQW in the E-k domain. In a preferred embodiment of the invention ring electrical contacts are disposed on the MQW and the entire MQW structure, including electrical contacts is mounted on a piezoelectric substrate, with the proper crystallographic orientation and strain induced orientation, via an epoxy.In operation, a bias is applied to the MQW structure and the piezoelectric substrate. The bias causes quantum decoupling of the heavy and light holes; however, the bias also will cause the piezoelectric material to move, which will induce a strain on the MQW structure.

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 imaging system for transferring an infrared (IR) image to a visible image. The imaging system includes a polarization rotator that rotates the polarization of a visible light beam in response to absorptions of radiation from the IR image. A polarizer outputs components of the visible light beam as a function of the amount of absorbed radiation from the IR image. The polarization rotator is formed from a multiple quantum well structure grown on a semiconductor substrate with a thermally induced uniaxial, in-plane, compressive strain. The multiple quantum well structure includes a heterostructure of undoped barrier layers and doped quantum well layers. The strain causes the quantum well layers to have anisotropic radiation absorption characteristics. In particular, orthogonal components of the visible light parallel to and perpendicular to the strain will experience different degrees of absorption.

Abstract: Porous silicon is formed by patterning a single crystal silicon substrate prior to electrochemically etching the same. The process is a controlled method of fabricating silicon microstructures which exhibit luminescence and are useful in optoelectronic devices, such as light emitting diodes. The porous silicon produced has a high degree of uniformity and repeatability.

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.

Abstract: The present invention is a spatial light modulator which uses an uniaxially trained multiple quantum well (MQW) structure with an anisotropic absorption to rotate the polarization of light normal to the MQW structure. The anisotropy which produces this rotation is the result of a thermally induced in-plane anisotropic strain. The MQW light modulator based on this process has a high contrast ratio of 7000:1 and increased speed as compared to other similar modulators.

Abstract: An optic modulator which employs strained multiple quantum well structures which are fabricated and spaced from one another such that the stress perpendicular to the direction of the spacing is released leaving only a uniaxial stress along the direction parallel to the spacing. The multiple quantum well structures are then sandwiched between two optic polarizers which are aligned perpendicular to one another. At zero electric field, polarized light passing from the first polarizer is further polarized such that the polarization of the light is rotated to pass through the second polarizer. When an electric field is applied across the heterostructure, light passing through the heterostructure is not further polarized and therefore, the optic signal is interrupted. Thus, optic signals may be modulated with the contrast of polarizing modulators at the speed of superlattice heterostructures.