Abstract: In an active region of an optical-electronic semiconductor device, nitrogen is incorporated in a barrier adjacent a GaNAs-based (e.g., GaInNAs) quantum well to improve device performance at wavelength bands above 1.2 microns. In a specific example embodiment, a mirror or cladding layer is grown over the active region in a manner that removes nitrogen complex otherwise present with Ga—N bonds in the active region. The embodiment can be implemented as one of a number of configurations including vertical cavity surface emitting lasers (VCSEL) and edge emitting lasers.

Abstract: A light detector comprising a photodetector disposed within an etalon or microcavity. The light detector is sensitive to light having a wavelength resonant with the etalon. Preferably, the etalon is a solid state microcavity having distributed bragg reflectors. The photodetector may be a photodiode, phototransistor or the like. The etalon has a front reflector with reflectivity Rf and a back reflector with reflectivity Rb. The photodetector has a double-pass absorption of A. In the present invention, Rf, Rb, and A are selected such that Rf=Rb(1−A). The combination of the back reflector and absorbing photodetector is indistinguishable from a single reflector of reflectivity Rf. Therefore, the light detector behaves like an etalon with matched reflectors. Preferably, Rf is greater than 0.95 and Rb is greater than 0.98. The photodetector can have a relatively thin absorption layer, thereby providing high speed capability.

Abstract: A system for determining wear of an article including an optical fiber for transmitting light from a light source. The optical fiber is embedded in the article, and operatively coupled to an interferometric system. The interferometric system is operatively coupled to a processor. The interferometric system provides the processor with information relating to wear of the optical fiber, and the processor determines wear of the article rate of wear and remaining useful life of the article based on the information relating to wear of the optical fiber.

Abstract: A method for fabricating gallium arsenide (GaAs) based structure groups with inverted crystallographic orientation to form wavelength converters that utilizes germanium as a crystallographic neutral template layer deposited on a GaAs substrate. A crystallographic inverted gallium arsenide layer is grown on top of the template layer. In a selective trench etching process areas of the substrate are exposed again for a consecutive collective deposition of GaAs.

Abstract: A group III-nitride quatenary material system and method is disclosed for use in semiconductor structures, including laser diodes, transistors, and photodetectors, which reduces or eliminates phase separation and provides increased emission efficiency and reliability. In an exemplary embodiment the semiconductor structure includes first GaAINAs layer of a first conduction type formed substantially without phase separation, an GaAINAs active layer substantially without phase separation, and a third GaAINAs layer of an opposite conduction type formed substantially without phase separation.

Abstract: A system for determining wear of an article including an optical fiber for transmitting light from a light source. The optical fiber is embedded in the article, and operatively coupled to an interferometric system. The interferometric system is operatively coupled to a processor. The interferometric system provides the processor with information relating to wear of the optical fiber, and the processor determines wear of the article rate of wear and remaining useful life of the article based on the information relating to wear of the optical fiber.

Abstract: A system for determining wear of an article including an optical fiber for transmitting light from a light source. The optical fiber is embedded in the article, and operatively coupled to an interferometric system. The interferometric system is operatively coupled to a processor. The interferometric system provides the processor with information relating to wear of the optical fiber, and the processor determines wear of the article rate of wear and remaining useful life of the article based on the information relating to wear of the optical fiber.

Abstract: A reversible and conservative photon routing switch is implemented as a room temperature, optical, vertical cavity X-gate (also sometimes known as a Fredkin gate). Such gates are primitive structures into which all logic functions can be decomposed. The construction of the device makes it uniquely suited to dense packed arrays of optoelectronic components for optical routing and logic. In one of the switching states, light incident on the device from either side of the wafer will pass through the device (the device is bi-directionally transmissive). In the other switching state, light incident from either side of the wafer will be reflected. Switching can be performed using either electrical or optical control. Thus incident photons are either routed through the device or reflected from the device.

Abstract: A microlaser is described which is electrostatically tunable. One of the reflectors includes at least one reflecting part whose distance from the other reflector can be adjusted to change the effective optical distance between the reflectors and thus tune the optical frequency at which lasing occurs. The disclosure brings out that the inventive aspect is also applicable to other optical devices having reflectors defining a Fabry-Perot cavity. An optical interconnecting scheme for processors using the microlaser is also described.

Abstract: A high-electron mobility transistor or HEMT has a top surface layer between its gate and drain arranged to produce a channel to drain conductance that is close to the ungated channel conductance to lower the output conductance and reduce gate leakage and gate capacitance. The transistor has a high band-gap active layer to produce a 2DEG channel in an adjacent layer, and source, gate and drain electrodes on the active layer. An undoped or lightly doped surface layer in the region between the gate and the drain produces a low conductance for a region of a few hundred .ANG. from the drain-side edge of the gate. This spreads the electric field domain over at least this few hundred .ANG. distance.

Abstract: The invention relates to an apparatus including a semiconductor grating whose optical properties can be changed electrically in order to steer a diffracted laser beam with no moving parts. Lithographically defined portions, stripes or areas formed in a semiconductor quantum well region used in association with selectable voltage supply means enable control of the optical characteristics of the grating. The optical properties of the semiconductor quantum well region vary in response to variations in voltage applied to the areas which in turn change the transmissivity or reflectivity of the areas. By selectively applying voltages, the diffraction pattern obtained in the far-field from illuminating the areas is thus controlled and beam steering results. By using a two-dimensional array of areas, or alternatively using two such one dimensional arrays, beam steering in two dimensions may be accomplished.

Abstract: A field effect transistor (FET) structure suitable for use at microwave frequencies is fabricated on a planar surface of a semi-insulating single crystal GaAs substrate which has been cut and polished to present the (110) surface. This orientation is selected because of its non-polar and other unique surface and interface properties. The (110) crystal axis is tilted from the normal of the planar surface in the direction to expose more of the (111) Ga face about 5.degree. to facilitate molecular beam epitaxial (MBE) growth of smooth, defect-free thin films. An elongate gate electrode is formed along the bottom of an anisotropically etched trench having a pair of longitudinal sidewalls, one vertical and the other tilted outwardly. The trench is selectively oriented on the substrate to facilitate such anisotropic etching.

Abstract: A method and apparatus for performing optical processing on optical information corresponding to a subject (66) combines known optical processing techniques with holography. A reverse ray-trace holographic system is provided so that the image reconstruction beam (90) passes through the optical system in a direction exactly opposite to that travelled by the subject beam (50) during recording of the hologram (88). Aberrations introduced by the system optics are then completely compensated for, allowing use of lower quality optical components. A single large-aperture lens (68) is used to define a Fourier transform of the optical subject information as the hologram (88) is recorded or the image reconstructed, and the subject information is manipulated within the Fourier transform plane (91).

Abstract: An apparatus for the production of a holographic image of a subject disposed at a subject plane includes a source of coherent light divided by a beamsplitter into a reference beam and a subject beam. The subject beam is directed towards the subject through a beamsplitter and a quarter-wave plate. The front surface of an opaque subject or a mirror behind a transparent subject reflects the subject beam back through the quarter-wave plate to the beamsplitter where it is deflected towards a photo-sensitive recording medium through an imaging lens. The reference beam is simultaneously directed toward the recording medium at a predetermined angle of incidence. After exposure and development of the medium, it is illuminated from the conjugate direction by the redirected reference beam. Image rays exactly retrace their original paths back through the optical system and provide a three-dimensional real-image reconstruction at the subject plane.

Abstract: A charge coupled device has a semi-insulating semiconductor for a substrate. Resistivity of the semiconductor is at least 10.sup.6 ohm cm. A semi-conductive layer is grown epitaxially or is implanted on the substrate to form a thin, active, charge transport layer. A row of parallel, closely spaced gates on the charge transport layer provides individual storage wells in the charge transport layer. In a preferred embodiment, ohmic contacts adjacent the first and last gates in the row of gates provide a means for injecting a signal into the charge transport layer and a means for detecting the signal. Preferably, the substrate is semi-insulating GaAs and the gates are Schottky barrier gates.

Abstract: A solar cell is constructed by coating an n-type conductivity semiconductor with a thin layer of bromine doped, polymeric sulfur-nitride, (SNBr.sub.0.4).sub.x. Metal deposits are provided on both materials for making electrical contact to the cell. In a preferred embodiment, the semiconductor is silicon. In a second preferred embodiment, the semiconductor is GaAs on an n.sup.+ -type conductivity GaAs substrate.

Abstract: A high-speed, light emitting device which utilizes a solid state source for generating light for use in fiber optical communications. The source is an active, narrow band gap layer of semiconductive material between heterojunctions formed with a p.sup.+ -type material on one side of an n.sup.+ -type material on the other side. A mirror on the back of the source reflects light toward an optical fiber abutting the substrate on the front of the source. A side mirror traverses the edge of the active layer at an angle of about 45.degree. and reflects light traveling parallel to the active layer toward the optical fiber. Contacts are coupled to the semiconductor material for applying an electrical signal across the active layer to generate light. In a preferred embodiment, the active layer is GaAsSb joined to GaAlAsSb and the substrate is GaAs.