Abstract: A junction field effect transistor, specifically a static induction transistor. The N-type source regions are formed as two zones. First, relatively lightly doped first zones are formed by ion-implanting doping material relatively deeply into the semiconductor material. Then relatively heavily doped second zones are formed by ion-implanting doping material to a relatively shallow depth within the first zones to leave portions of the first zones interposed between the second zones and the remainder of the semiconductor material. The resulting devices exhibit reduced gate-drain junction capacitance at low drain bias voltages thereby improving device capacitance linearity.

Abstract: Method of fabricating a junction field effect transistor employing self-alignment techniques. The active regions of the device are defined by a relatively thin thermally-grown isolating silicon oxide layer at the surface of a silicon body. After the active source and gate regions of the device as defined by the thermally-grown isolatign silicon oxide are formed in the silicon, a layer of deposited silicon oxide is formed over the thermally-grown silicon oxide. This method provides a thick dielectric layer as well as control of the horizontal dimensions of the source and gate contacts.

Abstract: A method and apparatus for high speed transmission of data in the solar blind region is disclosed. An ultraviolet source is modulated to permit digital transmission of data. The source includes an electrodeless capsule of UV transmitting material filled with iodine vapor. A means of energizing the iodine vapor into a plasma state is provided by a magnetron, power triode or solid state supply. A circuit to modulated the energizing means is used to impress upon the plasma discharge the encoded data. Filtering means surround the capsule to filter out the plasma background noise. The advantages of the UV communications method and apparatus described are increased pulse rate, faithful conversion of electrically pulsed data into optical pulses with decreased error rate, decreased probability of interception and non-line of sight communication.

Abstract: A semiconductor optical amplifier is utilized for optical amplification and for detection of an optical signal at the current injection electrode of the optical amplifier. A wide detection bandwidth is provided by utilizing an impedance transformer between the current injection terminal and the detection circuit. The impedance transformer typically has an input impedance of about 1 to 15 ohms. The impedance transformer can be a bipolar junction transistor circuit, a microstrip transmission line impedance transformer or a hybrid impedance transformer. A wide detection bandwidth is also obtained by providing a semiconductor optical amplifier having two current injection electrodes. A bias current is supplied through both current injection electrodes, and both electrodes produce optical gain. However, only one of the electrodes is used for optical signal detection. The detection electrode has a relatively high junction resistance and a relatively high series resistance.

Abstract: A waferboard assembly incorporates mechanical registration features into a substrate platform to facilitate the passive alignment of lasers integrated on a chip to fibers in integral contact with the substrate. The waferboard includes two front pedestal structures and one side pedestal structure, and two vertical post structures within a mounting region defined by the pedestal structures. The laser chip is mounted on the vertical post structures, and placed in concurrent abutting contact with the pedestal structures. The waferboard is fabricated by etching the substrate to form the front and side pedestal structures, and etching the substrate to define the grooves. In order to form the post structures, a polyimide material is deposited on the substrate using an appropriate mask.

Abstract: A ridge-waveguide laser is fabricated by epitaxially growing a GaAs-based heterostructure, disposing an AlAs etch stop layer on the heterostructure, disposing epitaxial layers on the etch stop layer, and etching the heterostructure to form the laser whereby the etch stop layer prevents further etching into said heterostructure.

Abstract: A method and apparatus is disclosed for assembling an array of optical fibers in a substrate. The method comprises forming a series of parallel V-shaped grooves in the top surface of the substrate placing the substrate on a base plate positioning an upper plate in spaced apart relationship with the substrate so as to form channels between the upper plate and the V-shaped grooves. A vacuum is then applied at one end of the channel formed between the upper plate and the V-shaped grooves, and optical fibers are then sequentially fed into each of the V-shaped grooves and are drawn into the grooves to a stop at the other end thereof. The fibers are then bonded to the substrate.

Abstract: A superconducting coil assembly. The assembly includes an insulating substrate, a plurality of insulating layers disposed in a stacked assembly on the substract, and a superconducting spiral pattern between the substrate and the adjacent insulating layer and between each adjacent pair of insulating layers. Superconducting connecting portions connect the spiral patterns to form a continuous thick film superconducting coil of right hand or left hand orientation. The spiral patterns and connecting portions are thick films of a high temperature ceramic superconducting material. A superconducting connecting link may interconnect the ends of the continuous coil to form a closed loop. The insulating layers and spiral patterns may be deposited successively over an insulating substrate. Alternatively, the insulating layers may be annular disks with vias therethrough for connecting the spiral patterns.

Abstract: A broadband space tree-switch matrix establishes a desired switching path by sensitizing only the sequence of logic gates defined by the desired path such that only these sensitized logic gates are operable to undergo switching and thereby permit transmission of only the corresponding input signal. The tree-switch includes a plurality of cascaded stages wherein the first stage consists of dual-input NAND gates each receiving a corresponding input signal at one input and a control signal at another input. The remaining stages include a plurality of switching nodes each having a first NAND gate cascaded to a second NAND gate wherein the second NAND gate has a HIGH steady-state logic signal present at one of its inputs. An appropriate combination of control signals are applied to the NAND gates in the first stage to effect a selected switching path. A second broadband space switch matrix comprises a plurality of NAND gates arranged into a series of cascaded stages to form a tree-switch configuration.

Abstract: System for distributing video programs includes a transmission system having a plurality of channels, includes a stored database representing a predetermined schedule including timing instructions. A computer is programmed to provide real time outputs in response to the database time instructions. A bus has an input coupled to the computer and providing control signals in response to the real time outputs. A recorded media contains programs in television format. A plurality of video players are used for playing the recorded media, each video player having a control port coupled to the bus and responsive to the control signals. Each video player has an output providing television signals for coupling to a separate corresponding channel, and at least two of the video players loaded with duplicate recorded media and controlled to play at staggered overlapping time intervals.

Abstract: A method of making fully dense, crack-free silicon nitride articles using polysilanes as a binder. Polysilane is dissolved in a solvent and a silicon nitride composition including a densification aid is added to form a homogeneous mixture. The mixture is dried to form a powder, and molded at a temperature less than 100.degree. C. to form a molded article. Alternatively, the slurry is poured into a mold and vacuum filtered to form a cake, then isostatically pressed at a temperature of approximately 90.degree. C. The molded article or pressed cake is heated at a rate of approximately 5.degree. C./min to about 900.degree. C. in a nonoxidizing atmosphere and held at about 900.degree. C. for a time sufficient to decompose the polysilane. The article is sintered in a nonoxidizing atmosphere at a temperature of about 1685.degree.-1900.degree. C. to form a silicon nitride article free of cracks and having a density greater than 3.5 g/cc.

Abstract: A method of passively aligning optical receiving elements such as fibers to the active elements of a light generating chip includes the steps of forming two front and one side pedestal structures on the surface of a substrate body, defining a vertical sidewall of the chip to form a mating channel having an edge at a predetermined distance from the first active element, mounting the chip epi-side down on the substrate surface, and positioned the fibers in fiber-receiving channels so that a center line of each fiber is aligned to a center line of a respective active element. When mounted, the front face of the chip is abutting the contact surfaces of the two front pedestals, and the defined sidewall of the mating channel is abutting the contact surface of the side pedestal. The passive alignment procedure is also effective in aligning a single fiber to a single active element.

Abstract: An apparatus for coupling light from a laser chip into an untreated, unetched optical fiber includes a mounting block to which is attached the chip, and a substrate carrier attached to the block and having a channel space extending axially through the substrate carrier. The fiber has a beveled end with an inner and outer face and is positionable within the channel space such that light emitted by the laser chip strikes the inner face of the beveled end and is totally internally reflected into the fiber core. In an alternate coupling assembly, light from the laser chip is reflected by a mirror to form a beam spot on the inner face of the beveled end where it is likewise totally internally reflected into the fiber.

Abstract: A method for fabricating a microelectronic device of the metal/insulator/metal' type wherein the insulator is an organic material, and a device fabricated thereby. A first electrically conductive lead is conductively adhered to a first portion of a conductive substrate. A monomolecular layer of highly pure p-dodecyloxyphenylcarbamate of 2-(2'-hydroxyethoxy)-5-bromo-7,7,8,8-tetracyanoquinodimethan is deposited on a surface of a second portion of the conductive substrate not including the first portion to form an organic film. Molecules of the monomolecular layer are generally disposed normal to the substrate surface with their dodecyl terminal moieties adjacent the surface. An essentially oxide-free contiguous layer of magnesium is deposited on the organic film. The deposition if performed at a temperature below about 15.degree. C. A layer of silver is deposited on the magnesium layer to substantially cover and conductively adhere to the magnesium layer.

Abstract: A method of encoding speech includes a limited search of a tree-code excitation codebook with a closed loop gain calculation for each test path under consideration. The gain calculation occurs when minimizing an error distance measurement between a synthetic signal defined by each test path being considered and the appropriate speech signal by optimizing a scaling factor of the synthetic signal. The encoding method achieves a significant reduction in computational complexity with minimal loss of performance.

Abstract: A locking circuit for controlling access to locked segments of a shared memory includes a content-addressable memory for storing addresses of the locked memory segments and for simultaneously comparing a target address with the addresses of the locked memory segments and providing a match signal when the target address matches one of the addresses of the locked memory segments. During a memory access cycle, a target address is supplied to the content-addressable memory, and a control circuit is responsive to the match signal to inhibit completion of the memory access cycle. A locking ID, which identifies the processor or process that locked the memory segment, is stored in a second memory. During a memory access cycle, a requesting ID is compared with the locking ID of the locked segment which produced the match signal. When the locking ID and the requesting ID match, the memory access cycle is enabled.

Abstract: An optical communication system includes a transmitter for generating a subcarrier multiplexed optical signal, a receiver and an optical fiber for coupling the optical signal from the transmitter to the receiver. At the transmitter, an optical carrier is modulated with a composite modulation signal including a plurality of modulated microwave subcarriers to provide the optical signal. The receiver includes a local oscillator for generating a local light beam, a detector responsive to the received optical signal and the local light beam for providing a detected signal at an intermediate frequency, and a microwave receiver for demodulating the microwave subcarriers from the detected signal. The modulation index of the optical signal produced by each of the modulated microwave subcarriers is selected to permit transmission of a large number of high quality video channels. A quadrature detector can be used to eliminate second-order intermodulation products.

Abstract: An optical switch for arbitrarily polarized light having low cross-talk is made in which an input beam is split into its TE (s wave) and TM (p wave) polarization components, the TM component is converted to TE by total internal reflection, the two beams are either reflected or transmitted by liquid crystal cells, one of the beams is then converted to TM polarization, again by total internal reflection, and the two beams are recombined and outputted from one of two ports.

Abstract: A junction field effect transistor, specifically a static induction transistor. Prior to metallization a thin layer of germanium is placed over the exposed silicon of the source and gate regions. The germanium is intermixed with the underlying silicon to form a germanium-silicon composite. A rapid thermal anneal is performed to recrystallize the germanium-silicon composite. Alternatively, a single crystal epitaxial layer may be deposited on the silicon. Conventional metallization procedures are employed to produce ohmic source and gate contact members to the germanium-silicon composite or the epitaxial germanium of the source and gate regions. By virtue of the reduced bandgap provided by the presence of the germanium, the contact resistance of the device is reduced.

Abstract: A narrow passband, reflective optical filter at a wavelength L, has a container filled with a pressurized gas, the pressurized gas having a ground state transition corresponding to the wavelength L and transparent to all other wavelengths. The container has at least one optically transparent major planar surface serving as the face thereof, whereby incoming broadband light is absorbed by the gas, except at its resonance wavelength L, which is specularly reflected. The optically transparent face of the container optionally has a broadband anti-reflective coating to improve its out-of-band rejection of unwanted wavelengths of the light signal.