Abstract: A floating gate memory device comprises a channel for conducting carriers from source to drain, a semiconductor heterostructure forming a potential well (floating gate) for confining carriers sufficiently proximate the channel so as to at least partially deplete it, and a graded bandgap injector region between the control gate and the floating gate for controlling the injection of carriers into and out of the potential well. Also described is a three element memory cell, including the memory device and two FETs, which operates from a constant, non-switched supply voltage and two-level control voltages. Arrays of memory devices may also be used to detect light in a variety of applications such as imaging.

Abstract: An efficient N.times.N star optical coupler suitable for mass production in integrated form is disclosed. The coupler can be realized using silicon technology to form a dielectric coupler slab and two arrays of strip waveguides all on a single glass substrate. Power transfer betwen the two arrays is accomplished through radiation in the dielectric slab with theoretical efficiency exceeding 30% under optimized conditions.

Abstract: An optical fiber sensing system for detecting intrusion of optical fiber or optical fiber cables includes an interferometric arrangement. Two ports (28, 30) of a four port splitter (25) are connected to a source (26) of optical power such as a laser, for example, and to a detector (32). The other two ports (46, 48) are connected to ends of a length (50) of monitoring optical fiber. An input signal to the splitter is split with one subsignal being directed in one direction around the length of optical fiber which serves as a common path between the two ports. The other signal is caused to travel around the common path in an opposite direction. The split signals are recombined in the splitter and their phase difference measured as a detectable pattern by the detector. Should there be intrusion of the optical fiber or a cable containing the monitoring optical fiber, the pattern which is detected will change a significant amount.

Abstract: To overcome the deleterious effects of the nonuniform frequency modulation response in semiconductor lasers due to current injection in direct frequency modulation applications, it has been determined that the linewidth enhancement factor .alpha. be made as large as possible. In one embodiment, distributed Bragg relector lasers well suited for frequency modulation lightwave communication systems are designed to have an integrated feedback element such as a corrugation grating whose effective pitch is selected to cause the Bragg wavelength and, therefore, the laser operating wavelength to be longer than the wavelength at substantially the maximum gain or gain peak in the semiconductor structure. That is, the wavelength of the grating is effectively detuned toward the longer wavelength and lower energy side of the peak of the gain profile.

Abstract: In a receiver for receiving and decoding a baseband multilevel signal into a digital data signal, and A/D converter produces in addition to the decoded data bits a "soft" bit, which inherently indicates the error polarity of the baseband signal. The soft bits are binary added to the most significant data bits to produce a sum bit. The sum bits are integrated, and the integral is used in a feedback loop to control the baseband signal amplitiude.

Abstract: Lower switching energies, enhanced electroabsorption and reduced tolerances on the operating wavelength of incident light are achieved while contrast between low and high absorption states is maintained in accordance with the principles of the invention by a self electrooptic device including an intrinsic quantum well region having an asymmetric electronic characteristic across a narrow bandgap subregion between the two wide bandgap layers defining the quantum well region. As a result, the quantum well region polarizes electrons and holes within the subregion in an opposite direction relative to a direction for an electric field applied to the device. The asymmetric electronic characteristic is realized as a compositionally graded, narrow bandgap layer or as a pair of coupled narrow bandgap layers of differing thicknesses separated by a thin wide bandgap layer.

Abstract: Photomasks (11, 12) are aligned on opposite sides of a wafer by directing light beams through zone plates (13 A-C) in one photomask and through aligned transparent slits (14 A-C) on the other photomask. Simulantaneous detection of the beams by photodetectors (18 A-C) indicates alignment. A method for obtaining precise centering by scanning the slits with the beams, sampling light transmitted through the slits, and fitting the samples to a parabola by the use of a computer (27) is also described.

Abstract: A semiconductor integrated resonant-tunneling device having multiple negative-resistance regions, and having essentially equal current peaks in such regions, is useful as a highly compact element, e.g., in apparatus designed for ternary logic operations, frequency multiplication, waveform scrambling, memory operation, parity-bit generation, and coaxial-line driving. The device can be made by layer deposition on a substrate and includes a resonant-tunneling structure between contacts such that side-by-side first and third contacts are on one side, and a second contact is on the opposite side of the resonant-tunneling structure.

Abstract: Real space hot electron transfer devices using hot electron transfer between two conducting channels are described.

Abstract: A novel analog comparator having cascaded gain stages powered by two buses, the voltages on which are dependent on a reference input voltage. A network, responsive to the reference input voltage, sets the voltages on the buses and isolates the buses from external power and ground to achieve high power supply and ground noise immunity. An alternative design of the network is provided which removes errors in the accuracy of the comparator resulting from differing drain-to-source voltages across the various transistors. The accuracy of the comparator is then dependent on the accuracy of matching predetermined ratios of the sizes of the transistors.

Abstract: A power converter includes an input primary switching system with its output connected to phase shift or impedance inversion circuit. These two circuits cooperate to function as a current source at the output of the impedance inversion circuit. A secondary switching system is connected in parallel with the output of the impedance inversion circuit and is switched synchronously with a controlled phase delay to the input primary switching system to synchronously charge a charge storage capacitor. The phase delay determines the voltage of the charge storage capacitor. An output load circuit is connected in parallel with both the output of the impedance inversion circuit and the input to the secondary switching system so that the capacitor voltage determined by the phase delay is controlling of the output voltage of the output load circuit.

Abstract: A self oscillating converter with regenerative switching includes circuitry to enhance the gain of circuity to turn off a MOSFET power switch and enhance the regenerative action culminating in turn off in order to eliminate bursting at low loads. The MOSFET power switching device turn off circuitry includes the addition of a supplementary drive transistor operative for counteracting the effects of the parasitic capacitances of the MOSFET power switching device. This permits the converter to operate with the shorter on times and to provide a low ripple output at very low load.

Abstract: An adaptor for interfacing a surface mount or through-hole electrical component to a printed circuit board. In one orientation of the adaptor relative to the printed circuit board, the adaptor receives a through-hole component and interfaces this component to a printed circuit board position designed for a surface mount component. In another orientation of the adaptor relative to the printed circuit board, the adaptor receives a surface mount component and interfaces this component to a printed circuit board position designed for a through-hole component. Advantageously, the adaptor is compatible with high-volume assembly techniques, such as wave soldering and machine insertion.

Abstract: A conductive polymer interconnect structure (10) is comprised of an insulative polymer (18), a silicone or an epoxy, having a plurality of particles (20) arranged therein to provide conductive paths which extend in the z direction. At least a portion of those particles (20) proximate a separate one of the major surfaces of the matrix has at least a portion thereof coated with a solder 24 whose composition is tailored to melt below the cure temperature of the matrix (18). In this way, when the matrix (18) is sandwiched between a pair of conductive members (12 and 14) and the matrix is cured, a metallurgical bond, rather than a mechanical bond, will be formed between the members.

Abstract: The integrity of surface structural features (e.g., distributed feedback gratings) in Group III-V compound semiconductors are preserved during heating (e.g., subsequent LPE regrowth) by a thin coating containing a transition metal (e.g., Os, Ru or Rh). DFP-DCPBH InP/InGaAsP single frequency lasers made in this way are also described.

Abstract: In a multiprocessor system, a program's execution that is controlled by controlling an extended process that spans a plurality of processors. The extended process comprises an user process on one processor for executing object code of the program and stub processes each on an individual one of said remaining processors for accessing system resources required for execution of the program. Each stub process gives the extended process access to the resources associated with the processor executing the stub process. Further, a stub process is unique to one particular extended process. Each stub process is interconnected to the user process by an individual virtual communication channel. The virtual communication channels are identified in each process by a port table that is unique to an individual process. When the user process accesses a local file, the access is through a user file table, a system file table, and an inode table.

Abstract: An insulation system and method utilizes multiple helically wound insulating tape windings wound on a wire. Each individual insulating tape winding is wound so that each wrap overlaps a specified area of the preceding wrap of the winding.

Abstract: A new associative computation network that is capable of storing multi-bit vectors includes a decision network and a feedback arrangement that, functionally, is separable into serially connected networks. The first network has its inputs connectd to the outputs of the decision network and is arranged to develop sets of excitatory and inhibitory drive signals. Each set corresponds to a stored vecor. For each different output state of the decision network, a different one of the drive signal sets appears at the output of the first network. The output leads of the first network, which may also be employed as the input interface leads, are connected to the second network. The second network develops output signals, applied to inputs of the decision network, which are proportional to the projection of the input signals applied to the second network on the stored vectors.

Abstract: An apparatus for releasably engaging a semiconductor wafer (12) comprises a frame (18) adapted for engagement by a robotic arm (26). The frame mounts one end of an elongated arm (30) dimensioned for insertion into a pocket (14) in a wafer-carrying cassette (16). The arm has a first jaw (34) depending from its end distant from the frame for engaging a portion of the edge of the wafer. A second jaw (38) extends through a slot (46) in the arm so as to be opposite the first jaw for engaging a portion of the edge of the wafer diametrically opposed to that engaged by the first jaw. The second jaw is displaced to and from the first jaw by a pneumatic cylinder (48) to enable the wafer to be releasably captured between the jaws without any damage to the surfaces of the wafer.

Abstract: A terminal block (20) includes a plurality of wells each having a protector 32) disposed therein and each having a bore which communicates with a U-shaped terminal (60) so that a portion of the protector extends through the bore into engagement with a bade (66) of the terminal. Tangs (68--68) of each terminal depend downwardly. Also, the terminal block includes a plurality of terminal posts (62--62) each having a spade (69) depending therefrom. A first plastic material (70) encapsulates the base and innermost portions of each U-shaped terminal and post. Individual conductors of a pair in a cable (50) extend to a depending tang of a terminal and to a tang of an associated terminal. A strap wire interconnects the other depending tang of each U-shaped terminal to a spade of an associated terminal post. A second plastic material encapsulates the wiring and the outermost portions of the U-shaped terminals and of the spades of the terminal posts.