Abstract: The disclosed novel method of making III/V semiconductor lasers involves cleaving of the wafer along predetermined cleavage planes. A cleavage plane is defined by means of aligned non-continuous depressions. The depressions are spaced from the laser contact regions, and typically are V-grooves produced by photolithography and anisotropic etching. A further surface feature, typically a precisely positioned scribe mark, facilitates cleavage initiation. When carried out in vacuum the novel method can provide high quality, accurately positioned cleavage surfaces, and consequently can facilitate increased yield of high power lasers.

Abstract: A CPE such as an ISDN telephone subset or multimedia equipment includes an interface recognition unit that connects to the network interface and adapts itself to allow the CPE to be used with standard ISDN interfaces and an analog interface. The interface recognition unit includes an interface recognition switch (IRS) that performs two functions. First, the IRS protects the CPE from damage in those instances where a non-standard network interface is connected to the CPE. Second, for standard interfaces, it identifies the type of network interface and routes the incoming signals appropriately. Specifically, if the IRS detects a T interface, the incoming signals are switched directly to a T interface circuit for controlling and powering the higher functions of the CPE. If the IRS detects a U interface, incoming signals are automatically switched to a U interface circuit for controlling and powering the CPE.

Abstract: Disclosed is a method for error recovery in a multiprocessing computer system of the type in which each of the processes periodically takes checkpoints. In the event of a failure, a process can be rolled back to a prior checkpoint, and execution can continue from the checkpointed state. A monitor process monitors the execution of the processes. Upon the occurrence of a failure, a target set of checkpoints is identified, and the maximum consistent global checkpoint, which includes the target set of checkpoints, is computed. Each of the processes is rolled back to an associated checkpoint in the consistent global checkpoint. Upon a subsequent occurrence of the same failure, a second set of checkpoints is identified, and the minimum consistent global checkpoint, which includes the target set of checkpoints, is computed. Each of the processes is rolled back to an associated checkpoint in the consistent global checkpoint.

Abstract: A method is provided for reducing the polarization shift between different modes of an optical signal propagating in an optical grating having a plurality of waveguides extending in a common plane. The method includes the step of imparting curvature to the optical grating along a line that traverses the plurality of waveguides in a direction that is substantially perpendicular to the direction in which the optical signal propagates. The curvature varies in a nonuniform manner along the line to which it is imparted. The curvature may vary in a substantially linear manner along this line, which in some cases may define a symmetry axis of the grating. Sufficient curvature may be imparted to substantially eliminate the polarization shift. The curvature may be imparted by flexing the optical grating at two contact points respectively located near a longest and shortest of the plurality of waveguides.

Abstract: A graphical user interface, i.e., multimedia communications application program, for setting up and handling a multimedia call is disclosed that employs realistic metaphors of real life face-to-meetings in setting up and handling a multimedia call to establish a virtual meeting which is automatically reconfigured in response to user action. This is realized by taking advantage of prospective virtual meeting participants' already existing knowledge of how real life face-to-face meetings operate. To this end, the multimedia communications application program enables the virtual meeting participants through direct manipulation of the realistic graphical metaphors to establish a realistic virtual meeting room which is displayed on the screen of their workstation monitor. The virtual meeting room includes a table and chairs arranged in a realistic manner in the virtual meeting room.

Abstract: Wavelength division multiplexing, spatial switching cross-connect structures which may be deployed as intermediate nodes of an all optical network to route any input channel on any source fiber to any destination fiber at any available wavelength to achieve full connectivity between the nodes of the network. The non-blocking cross-connect structure comprises a wavelength division demultiplexer for receiving multiple wavelength channels from each source fiber and for separating received channels into N wavelengths so that the wavelengths are organized according to a corresponding fiber of origin, a nonblocking optical structure for spatially and independently rearranging the received wavelengths so that wavelengths having a common destination fiber are grouped together, and a wavelength division multiplexer for multiplexing together wavelengths having the same destination fiber.

Abstract: Low optical loss and simplified fabrication are achieved by a nonlinear reflector which incorporates one or more semiconductor quantum wells within a standard semiconductor quarter wave stack reflector. The nonlinear reflector provides an intensity dependent response which permits it to be used for saturable absorption directly in a main oscillating cavity of a laser. Saturation intensity of the nonlinear reflector and thereby related laser modelocking properties can be controlled by disposing the quantum well at a particular position in the reflector structure.

Abstract: A method and apparatus for querying a disjunctive database is disclosed. An annotated object, which defines a complete object which is a unique element of the normal form of the database, is stored and maintained in memory. A complete object is created using the annotated object, and is stored in memory. A query is run against the complete object. If continued processing is required, a next function produces a next annotated object, which represents another unique element of the normal form of the database. The next annotated object is stored in memory, overwriting the previous annotated object. A complete object is then created using the next annotated object and is stored in memory, overwriting the previous complete object. The query is then applied to the complete object stored in memory. By processing the elements of the normal form one at a time and reusing memory spaces, the present invention has a polynomial space requirement.

Abstract: Methods are disclosed for finding maximal matches in data strings and for finding matches in parameterized strings, that is, strings containing symbols from more than one alphabet in which the symbols from one of the alphabet are treated as parameters. In general, such maximal matches are found by creating a suffix tree representing the data string, generating lists for each node in the tree indicating the left contexts of all suffixes associated with that node and reporting matches for pairs of suffixes having different left contexts. One method of finding parameterized matches is to substitute a common symbol for the symbols of the alphabet representing the parameters before creating the suffix tree and then discarding matches found for which the actual parameters are not consistent.

Abstract: A method and apparatus for quantizing audio signals is disclosed which advantageously produces a quantized audio signal which can be encoded within an acceptable range. Advantageously, the quantizer uses a scale factor which is interpolated between a threshold based on the calculated threshold of hearing at a given frequency and the absolute threshold of hearing at the same frequency.

Abstract: Optoelectronic devices such as photodetectors, modulators and lasers with improved optical properties are provided with an atomically smooth transition between the buried conductive layer and quantum-well-diode-containing intrinsic region of a p-i-n structure. The buried conductive layer is grown on an underlying substrate utilizing a surfactant-assisted growth technique. The dopant and dopant concentration are selected, as a function of the thickness of the conductive layer to be formed, so that a surface impurity concentration of from 0.1 to 1 monolayer of dopant atoms is provided. The presence of the impurities promotes atomic ordering at the interface between the conductive layer and the intrinsic region, and subsequently results in sharp barriers between the alternating layers comprising the quantum-well-diodes of the intrinsic layer.

Abstract: A split boost converter is disclosed herein, suitable for both single phase and three phase AC input applications. It provides two equal but unparallelable output voltages stored on two separate independent output capacitors. The implementation supports two modes of operation in which two power switches are operated simultaneously or alternately. Each mode maintains the advantage of a reduced boost inductor size. In the first mode the charging of the capacitors in parallel circuits and their discharge in a series connection substantially reduces ripple current in the inductor permitting the user of a smaller inductor. In the second mode the capacitors are charged and discharged in differing time intervals achieving a similar result. The circuit is operable with input voltages which must exceed the voltages of its two output capacitors.

Abstract: A novel non-mechanical optical fiber switch contains a magneto-optic element and a tubular magnet. The magneto-optic element is disposed within the field of the magnet but outside of the magnet bore. The beam of radiation from the switch input to the switch output passes through the axial bore of the magnet. The magnet contains magnetically anisotropic material, preferably a deformation-aged alloy having Fe, Cr and Co as major constituents. The switch is advantageously used in optical fiber communication systems.

Abstract: Increased coverage and macro diversity from a single base station in a wireless communication system by having a base station coupled to N antennas is described. Increased coverage and macro diversity are achieved by transmitting from the base station N control messages each via one of the antennas, and transmitting a data message addressed to a mobile unit via a particular one of the antennas previously assigned to the mobile unit for an active call. The mobile unit receives the control messages and the data message and analyzes the control messages to identify from the antennas a best antenna. The mobile unit then transmits to the base station a new antenna request identifying the best antenna in an uplink control slot of a frame. The uplink control field is associated with the particular one of the antennas. The base station uses the best antenna to transmit subsequent data messages addressed to the mobile unit.

Abstract: The invention permits various types of background knowledge for a concept learning system to be represented in a single formal structure known as an antecedent description grammar. A user formulates background knowledge for a learning problem into such a grammar, which then becomes an input to a learning system, together with training data representing the concept to be learned. The learning system, constrained by the grammar, then uses the training data to generate a hypothesis for the concept to be learned. Such hypothesis is in the form of a set of logic clauses known as Horn clauses.

Abstract: Disclosed are methods and systems for achieving and maintaining data transmission rates in processing system networks, independent of communication between the node and the processing system network, and including techniques for data transmission initialization, data retransmission, and buffer management. Data transmission initialization includes transmitting data packets from a source node over a network at an adaptive exponential transmission rate from a current operating point to an optimal operating point. The optimal operating point is a data transmission rate wherein data buffers are neither overflowing nor under-flowing. Data retransmission includes transmitting data packets at the optimal set point, detecting the loss of a transmitted data packet as a function of a timer-less acknowledgement signal, and retransmitting the lost data packet.

Abstract: Duplicated optical detectors detect the removal of a printed circuit board and are also used as indicators to indicate conditions on the printed circuit board. The detectors comprise a controller, two pairs of light emitting diodes (LEDs), and two light pipes mounted through and secured to a latch handle attached to the printed circuit board. Each light pipe extends over a pair of LEDs in the closed position of the latch handle. One LED of each pair is utilized as a transmitter, and the other LED of the pair is utilized as a light sensor. In the closed position of the latch handle, light is communicated from the transmitter via the light pipe to the light sensor and through the latch handle to the back of the printed circuit board. For purposes of detecting the removal of the board, as the board is being removed, the latch handle pivots away from the board moving the light pipes from the closed position that is over the LEDs.

Abstract: A scanning probe microscope positioner including an elongated rigid member which is controllably tilted in a predictable manner. One end of the rigid member is subjected to differential motion on opposite sides of its longitudinal axis so as to cause its opposite end to partake of lateral displacement which is a magnification of the differential motion. By a careful selection of component materials and sizes, inherent thermal compensation can be attained.

Abstract: A surge protection cartridge adapted for use with a double-sided modular connector block system. The protector cartridge advantageously mounts in the front or rear of a connector module of the connector block in a variety of orientations in order to protect an entire row of terminations on the block. Two L-shaped brackets adapted to couple to a mounting bracket of the connector block form an internal ground bus within the protector cartridge. The brackets include a series of cantilever connecting clips which couple directly to the surge protection devices. Spring contacts having similar cantilever clips couple the remaining leads of the surge protection devices and the terminals of the connecting block which are to be protected. Each individual spring contacts is seated within an individual insulated well of the cartridge housing.

Abstract: In accordance with the invention, electronic packages comprising a layer of molded plastic on one side of an insulating substrate are provided with a surrogate layer on the side of the substrate opposite the molded plastic to reduce bending stress. The surrogate layer is preferably thin, has a high coefficient of thermal expansion and is resistant to high tensile stress. Advantageously, the surrogate layer is processed concurrently with the molding of the plastic. Preferred surrogate layers are low temperature thermoplastic sheets, such as acetal plastic sheets, that soften at the molding temperature sufficiently to bond to the substrate. Alternatively, they can be higher temperature rigid materials, such as glass fiber composites, bonded to the substrate with an adhesive layer that cures during molding.