Abstract: The invention provides a device having a substrate, a buffer region positioned upon the substrate, wherein the buffer region has an upper buffer region and a lower buffer region, a heterojunction region positioned upon the buffer region, and a superlattice positioned between the lower buffer region and the upper buffer region, wherein the device is configured to function as a heterojunction field effect transistor.

Abstract: An optical multiplexer and demultiplexer for dense wavelength division multiplexed (“DWDM”) fiber optic communication systems is disclosed. As a multiplexer, the device functions to spatially combine the optical signals from several laser sources (each of which is a different wavelength) and launch the spatially combined laser beams into a single optical fiber. As a demultiplexer, the device functions to spatially separate the different wavelengths of a wavelength division multiplexed optical link and launch each of the different wavelengths into a different optical fiber. In either embodiment, the device includes both bulk optic and integrated optic components. The spatial separation or spatial combination of laser beams of different wavelength is achieved with the use of bulk diffraction gratings.

Abstract: An optical multiplexer and demultiplexer for dense wavelength division multiplexed (“DWDM”) fiber optic communication systems is disclosed. As a multiplexer, the device functions to spatially combine the optical signals from several laser sources (each of which is a different wavelength) and launch the spatially combined laser beams into a single optical fiber. As a demultiplexer, the device functions to spatially separate the different wavelengths of a wavelength division multiplexed optical link and launch each of the different wavelengths into a different optical fiber. In either embodiment, the device includes both bulk optic and integrated optic components. The spatial separation or spatial combination of laser beams of different wavelength is achieved with the use of bulk diffraction gratings.

Abstract: An optical multiplexer and demultiplexer for dense wavelength division multiplexed (“DWDM”) fiber optic communication systems is disclosed.. As a multiplexer, the device functions to spatially combine the optical signals from several laser sources (each of which is a different wavelength) and launch the spatially combined laser beams into a single optical fiber. As a demultiplexer, the device functions to spatially separate the different wavelengths of a wavelength division multiplexed optical link and launch each of the different wavelengths into a different optical fiber. In either embodiment, the device includes both bulk optic and integrated optic components. The spatial separation or spatial combination of laser beams of different wavelength is achieved with the use of bulk diffraction gratings.

Abstract: An optical multiplexer and demultiplexer for dense wavelength division multiplexed (“DWDM”) fiber optic communication systems is disclosed. As a multiplexer, the device functions to spatially combine the optical signals from several laser sources (each of which is a different wavelength) and launch the spatially combined laser beams into a single optical fiber. As a demultiplexer, the device functions to spatially separate the different wavelengths of a wavelength division multiplexed optical link and launch each of the different wavelengths into a different optical fiber. In either embodiment, the device includes both bulk optic and integrated optic components. The spatial separation or spatial combination of laser beams of different wavelength is achieved with the use of bulk diffraction gratings.

Abstract: The invention concerns the fabrication and characterization of vertical geometry transparent Schottky barrier ultraviolet detectors based on n.sup.- /n.sup.+ -GaN and AlGaN structures grown over sapphire substrates. Mesa geometry devices of different active areas were fabricated and characterized for spectral responsitivity, speed and noise characteristics. The invention also concerns the fabrication and characterization of an 8.times.8 Schottky barrier photodiode array on GaN with a pixel size of 200 .mu.m by 200 .mu.m.

Abstract: A method and apparatus for automatically providing for both multiplexing and independent external modulation of two or more wavelengths emitted by one or more multi-longitudinal mode laser(s) or other light source. The present invention uses an integrated optics device chip to enable coupling of the dispersed wavelengths into separate electro-optic modulators which encode each of the carrier wavelengths with a different signal. Accordingly, the volume of data which can be transmitted over an optical fiber network is increased. The carrier wavelengths can be transmitted over single or multi-mode optical fibers.

Abstract: A method and apparatus for automatically providing for both multiplexing and independent external modulation of two or more wavelengths emitted by one or more multi-longitudinal mode laser(s) or other light source. The present invention uses an integrated optics device chip to enable coupling of the dispersed wavelengths into separate electro-optic modulators which encode each of the carrier wavelengths with a different signal. Accordingly, the volume of data which can be transmitted over an optical fiber network is increased. The carrier wavelengths can be transmitted over single or multi-mode optical fibers.

Abstract: A method and apparatus for splitting, scanning and receiving a beam of light is disclosed. Binary optic array components are used to split, in an angular manner, an input beam into multiple beams, traveling in different directions. Miniaturized array element BOCs arranged in "n" different groups are used, wherein n is dependent upon the number of split beams needed or desired. An offset is introduced between the optical axis of each of the corresponding pair of miniaturized BOCs. By varying the offset over time, the resultant beam(s) can be scanned in one, two or three dimensions. Piezo-electric drivers controlled by a processor may be used to move the array in order to vary the offset. The device may also include a collection area to collect the returned scanned beams by using an array of optic components integrated with the scanner. The collected beams are then focused onto detectors.

Abstract: A method and apparatus for automatically providing for both multiplexing and independent external modulation of two or more wavelengths emitted by a multi-longitudinal mode laser. The present invention uses an integrated optics device chip to enable coupling of the dispersed wavelengths into separate electro-optic modulators which encode each of the carrier wavelengths with a different signal. Accordingly, the volume of data which can be transmitted over an optical fiber network is increased.

Abstract: A high electron mobility transistor is disclosed, which takes advantage of the increased mobility due to a two dimensional electron gas occurring in GaN/Al.sub.x Ga.sub.1-x N heterojunctions. These structures are deposited on basal plane sapphire using low pressure metalorganic chemical vapor deposition. The electron mobility of the heterojunction is approximately 620 cm.sup.2 per volt second at room temperature as compared to 56 cm.sup.2 per volt second for bulk GaN of the same thickness deposited under identical conditions. The mobility of the bulk sample peaked at 62 cm.sup.2 per volt second at 180.degree. K. and decreased to 19 cm.sup.2 per volt second at 77.degree. K. The mobility for the heterostructure, however, increased to a value of 1,600 cm.sup.2 per volt second at 77.degree. K. and saturated at 4.degree. K.

Abstract: The invention is an Al.sub.x Ga.sub.1-x N ultraviolet detector with extremely high responsivity at over 200 to 365 nanometers and a very sharp long wavelength cutoff. The active layer for the sensors is a single crystal Al.sub.x Ga.sub.1-x N preferably deposited over a basal plane sapphire substrate using a switched atomic layer epitaxy process.

Abstract: A high electron mobility transistor is disclosed, which takes advantage of the increased mobility due to a two dimensional electron gas occurring in GaN/Al.sub.x Ga.sub.1-x N heterojunctions. These structures are deposited on basal plane sapphire using low pressure metalorganic chemical vapor deposition. The electron mobility of the heterojunction is aproximately 620 cm.sup.2 per volt second at room temperature as compared to 56 cm.sup.2 per volt second at 180.degree. K. and decreased to 19 cm.sup.2 per volt second at 77.degree. K. The mobility for the heterostructure, however, increased to a value of 1,600 cm.sup.2 per volt second at 77.degree. K. and saturated at 4.degree. K.

Abstract: The invention is a filter device of at least two layers, the first layer of Al.sub.x Ga.sub.(1-x) N and the second layer of Al.sub.y Ga.sub.(1-y) N wherein x and y may have any value from 0 to 1. The invention may be used as a fixed wavelength or tunable wavelength filter or in ultraviolet detectors and laser devices, among other systems. Applications for the invention include detection of UV radiation in environments having a high level of incident infrared and visible radiation, as well as applications requiring detection of UV emission when no other radiation is present.

Abstract: An improved aluminum gallium nitride material is disclosed, which permits the fabrication of improved optical devices such as laser mirrors (1, 2), as well as quantum wells and optical filters. The optical devices are constructed by depositing a buffer layer (7) of aluminum nitride onto a substrate (6), with alternating layers (10, 12, 14, etc.) of Al.sub.x Ga.sub.1-x N and Al.sub.y Ga.sub.1-y N, where x and y have values of between 0 and 1. Edge emitting lasers (31), surface emitting lasers (52) and quantum wells operating in the ultraviolet region are disclosed. The method of the present invention permits the ability to deposit thin, reproducible and abrupt layers of the improved material to permit the construction of rugged, solid state devices operating at ultraviolet wavelengths.

Abstract: A transmission holographic element (1) composed of a first reflection holographic optical element (2) and a second reflection holographic optical element (3). Reflection holographic optical elements (2,3) are adhesively mated such that the distance separating the two elements is no more than a few wavelengths of the incident light beam (9). The incident light beam (9) passes through first element (2) and is reflected off of the second element (3) which reflects the light beam back towards first element (2) which again reflects the light beam through the second optical element (3). In this manner, two discrete reflection holographic elements (2,3) behave as a single transmission holographic element.

Abstract: An integrated device (10) for scanning a laser beam, including a substrate (12). An electro-optic waveguide (14), a Bragg grating electrode array (31) in operative contact with the waveguide, and a array of electro-optic prisms (33). The electrode array (31) includes a plurality of upper grating electrodes (26) and a lower first electrode (32). A voltage potential can be placed across individual upper grating electrodes (26) and the lower electrode (32) to establish up a Bragg grating in a small localized region. This localized Bragg grating diffracts a laser beam carried by the waveguide and creates a spatially-variable diffracted beam (40) which can be continuously scanned by deflecting the diffracted beam (40) with the electro-optic prism array (33).

Abstract: A single-mode electro-optic switch (10 or 10') including a graded index layer (14b or 14b'). Two electro-optic embodiments are disclosed. The first embodiment includes a substrate (12) and a planar waveguide (14) atop the substrate (12) including a graded index layer (14b) sandwiched between a pair of lower refractive index layers (14a and b 14c). The substrate (12) preferably forms anisotropically etched V-grooves (38) suitable for receiving fibers (50) and (52) and for registering the cores of the fibers with the middle layer (14b). The first embodiment of the switch includes a single input port and a pair of output ports, wherein when the switch is energized, light is reflected away from the first output port and toward the second output port.