Abstract: A tunable semiconductor laser comprises a gain section having an MQW active region, a uniform pitch grating DFB region, and first waveguide. A composite reflector, including a second MQW region and a second waveguide, forms a cavity resonator with the DFB region. A voltage applied to the composite reflector induces a quantum confined stark effect, thereby allowing the wavelength to be altered. In one embodiment, the current drive to the active region and the shape of the first waveguide (e.g., a raised-sine function) are mutually adapted so that N longitudinal modes have essentially the same threshold gain and so that the DFB region spanned by the first waveguide is segmented into N zones, each zone providing optical feedback at a different wavelength corresponding to a different longitudinal mode.

Abstract: A wavelength selective resonant grating exhibits transmission resonances when a single gap between two sections of a split gratings is used to provide a phase shift which is not a quarter wavelength in length or .pi./2 in phase. When the phase is changed to non - .pi./2 values (or the gap differs from a quarter wave), the transmission resonance moves from the center of the stop band. Appropriate adjustments of the phase over a .pi. interval allow tuning of the resonance across the entire stop band. The resonant optical wavelength grating can, illustratively, be used as wavelength filter, wavelength monitor, or as part of an Add/Drop arrangement.

Abstract: The improved antenna system provides significant cost reduction and improves the modularity of the antenna system by combining the power supply lines and the control lines on a single line. Control circuitry is responsive to a power supply signal which acts as the power supply for the antenna system to control the operation of the antenna system. In certain embodiments, the improved antenna system is connected to a single line which carries communication signals and the power supply signal. As such, the antenna system combines the communication lines, the power supply lines and control lines to provide a modular antenna system at a reduced cost. In controlling the antenna system, the control circuitry can control the operation of signal circuitry, which handles the communication signals, in response to the control information provided by the power supply signal. The control circuitry can control other features of the antenna system, such as antenna diversity circuitry, in response to the power supply signal.

Abstract: An integrated circuit includes a converter for converting a signal from one form to another, one of the forms being analog and the other form being digital. The converter includes a voltage gradient having a plurality of MSB taps spaced there-along with the plurality of LSB taps spaced between adjacent MSB taps. An array of comparators are coupled to the voltage gradient with each comparator providing an output. A matrix of switches are coupled between the voltage gradient and the comparator inputs. The first inputs of the comparators in the array are coupled to a sample-and-hold circuit which provides a sample of the analog input signal. Decode and control logic are coupled to comparator outputs to provide a control to the matrix of switches to determine which taps of the voltage gradient are coupled as second inputs to the comparators in the array of comparators and also to provide the resultant output representation of the sampled analog input signal.

Abstract: In accordance with the present invention, an apparatus and method for implementing a new user-defined B-S instruction called PINCONTROL is disclosed. When PINCONTROL is in effect, an output pin can be configured to be either driving a constant 0, driving a 1, in the high-impedance (high-Z) state or in the control of system logic; and different pins of the same chips may assume different configurations depending on the content of the capture and update portion of the B-S register. This instruction provides an improved fault insertion capability. For example, if it is desired to inject a stuck-at-0 fault at pin p, pin p can be configured to drive a constant 0 while allowing other pins to function normally. A stuck-at-1 fault can also be injected by configuring pin p to drive a constant 0 while allowing other pins to function normally. An open fault can also be injected by configuring pin p into a high-impedance state.

Abstract: A technique for interference rejection at a sensor array is disclosed that employs a transformation on the output of the sensor array wherein the angular location of the source of each interfering signal constitutes the null-space of the transformation. For a sensor array of M sensor elements, the rejection of up to M-1 interferers is possible with a single transformation. One embodiment of the present invention comprises: receiving M signals, x.sub.0 (t) through x.sub.M-1 (t), at a frequency of .omega. radians/second at a sensor array comprising M spatially-disparate sensor elements, x.sub.0 through x.sub.M-1, wherein the M signals, x.sub.0 (t) through x.sub.M-1 (t), comprise a signal of interest incident on the sensor array at an angle .phi., and an interfering signal incident on the sensor array at an angle .psi..sub.1 ; transforming each of the M signals, x.sub.0 (t) through x.sub.M-1 (t), by a first factor based on .omega., .psi..sub.

Abstract: A method and apparatus for achieving alignment between a spray etcher nozzle and a semiconductor (either microelectronic or optoelectronic, for example) wafer surface. A spray nozzle tip is temporarily removed from the spray nozzle and an illumination source, such as a low power laser, is activated and inserted in its place. The laser emission illuminates the wafer surface and, by adjusting the position of the nozzle, alignment between the nozzle and wafer can be achieved. Once aligned, the nozzle is locked in place and the laser is replaced with the conventional spray nozzle tip.

Abstract: Allowing the implementation of a strictly nonblocking cross-point space switch central stage for the switching of SDH frames or other formats. The port terminating each incoming link has a time slot interchange (TSI) unit. Each TSI unit comprises incoming and outgoing sets of TSI's. The TSI's properly arrange each byte of each row of the STM-1 frame or other formats to be in the proper position for transmission on the STM-1 links. Within the STM-1 frame structure, each row of a frame is switched in an identical manner but the column designations within a row are switched differently. In response to rearranged frames from incoming TSI's, a cross-point switch is responsive to each column of each of the rows to switch each of the bytes of that column to the appropriate outgoing TSI for rearrangement and transmission on a STM-1 link.

Abstract: A fiber optic cable having stress indicating means and a method for making same. The stress indicating means provides a cost effective method for determining whether an optical cable has been bent, stressed or otherwise mishandled, which may cause optical loss when the cable is placed in service. Broadly stated, the fiber optic cable according to the instant invention includes an optical fiber, comprised of a core and a cladding and a stress indicator concentrically disposed about the fiber that changes color when subjected to stress. A technician can thereby visually identify cables that have been bent or mishandled and subject them to testing before installation.

Abstract: A method for efficiently acquiring and releasing a shared locking mechanism in a multiprocessor environment comprises updating variables associated with the locking mechanism and variables associated with processors seeking to acquire the lock. If the lock is currently occupied, a processor waits in accordance with information initialized in a spin variable associated with the processor. Upon releasing the lock, a relinquishing processor determines whether there are other processors waiting to acquire the lock. If other processors are waiting to acquire the lock, the relinquishing processor alters a successor variable associated with the waiting processor in the waiting processor's local shared memory so that the lock mechanism can be passed on and a first-in and first-out behavior of a waiting queue can be maintained.

Abstract: Automatic bias setting circuits for multiple quantum well (MQW) diodes and optical modulators generally are described. Both digital and analog circuits are provided and techniques for utilizing such circuits for monitoring and controlling optical modulator signal quality are disclosed. In one approach, a desired modulation voltage range is determined. A bias voltage is stepped from a first predetermined voltage up to a second predetermined voltage. A maximum differential photocurrent is determined and the bias voltage corresponding to that photocurrent is then employed so that optimal optical modulator signal quality is achieved. An advantageous application of this technique is in wavelength division multiplexed (WDM) systems in which different optical modulators are operating at different wavelengths. In such a system, a different voltage bias will typically be determined for each optical modulator.

Abstract: A test structure and test fixture which are capable of measuring time dependent dielectric breakdown under accelerated temperature test conditions which can extend to 300.degree. C. The test structure is a parallel plate configuration with metal electrodes which is insensitive to polarity.

Abstract: A semiconductor device comprises a signal pin mounted on a base plate by adhesive. Parasitic capacitance exists between the pin and the base plate in the region of adhesive and may deleteriously affect the operation of circuitry in chip connected to pin by a bond wire. A bond wire connecting pin to the base plate has an inductance which forms a parallel resonant circuit with the parasitic capacitance, so that, at the resonant frequency, signals on pin at substantially the same frequency pass to or from the chip substantially unattenuated by the parasitic capacitance. Alternatively, the inductances of the signal pin and the bond wires may be such that, at the frequency of signals on the signal pin, an impedance transformation is provided between the input to the signal pin and the end of the first bond wire where it connects to the chip.

Abstract: A system (100) that is capable of transmitting a displayable message to a short message entity (102, 104 or 105) in more than one data package over a conveying network. The system (100) uses a capacity determiner (206) to determine a capacity of the conveying network for transmitting data. Based on this capacity of the conveying network, a fragmenter (204) divides the displayable message into fragments at an application protocol layer. The size of a fragment does not exceed the capacity of the conveying network. Finally, a packager (208) packages the fragments into data packages. The data packages are operable to be separately transmitted by a short message service over the conveying network. The data packages may include a reference parameter corresponding to the position of the fragment in the displayable message. Further, a reference parameter may indicate the total size of the displayable message being fragmented and packaged.

Abstract: In accordance with the present invention there is provided a tristatable digital MOS output buffer/driver having a significantly reduced subthreshold leakage current. The buffer of the present invention comprises three P-channel transistor devices and three N-channel transistor devices. A reduced subthreshold leakage current is achieved by having the source of the output N-channel transistor device and the output P-channel transistor device connected to nodes having a variable voltage. This adjusts the source-to-body voltages of the output N-channel and P-channel transistor devices to be equal in magnitude to the voltage of the positive supply, resulting in the reduction of subthreshold leakage currents.

Abstract: List Viterbi algorithms are provided for decoding blocks or frames of convolutional coded information transmitted and received in a continuous mode, i.e., without blockwise termination with a tail. Viterbi decoding is utilized to estimate, for each respective one of a sequence of blocks of symbols, a terminating (and optionally a starting) state which is(are) used in subsequent application of a List Viterbi algorithm. The path memory should be sufficient to enable both the starting state and the terminating state used by the subsequent List Viterbi decoding to be estimated with reasonable accuracy and at the same time to keep track of the best paths between those states.

Abstract: A universal fixture has an alignment surface which temporarily holds a heat sink for installation of a plurality of electrical devices on its working surfaces. The fixture rotates about an axis to place an alignment surface in a first or second mounting position corresponding to a generally vertical orientation of the alignment surface. This corresponds to a horizontal position of the opposite first and second sides of the heat sink temporarily mounted thereon. Double rows of openings in the rotatable alignment member are universal in the sense they are configured to accept connection pins of the common packages to be clamped against the opposite sides of the heat sink. This permits one fixture to accommodate a variety of devices and arrangements. A unique standoff device supports smaller packages above the alignment surface to permit clamping across larger and smaller electrical devices without the necessity of attempting to manipulate and hold the devices by hand during the clamping operation.

Abstract: Disclosed is a device for reducing crosstalk in an electrical connector. The device includes an insulating board with a plurality of layers. A first plurality of pairs of conductive paths is formed on a surface of at least one layer, and a second plurality of pairs of conductive paths is vertically spaced therefrom. The paths are arranged so that at least one conductive path in the first plurality of pairs overlies at least two conductive paths from different pairs in the second plurality of pairs. The capacitive coupling between the paths results in crosstalk having a polarity opposite to that of the connector so as to compensate for the connector crosstalk.

Abstract: In this invention, a computer program stored in the memory of a computer is used to mine preexisting data located in a variety of preexisting source databases. The computer program either creates a new database from parts of existing databases or modifies an existing database. The computer program replaces the current system's reliance upon manual data entry by data engineers to configure the operation of a new telecommunication switch or replace the software in a telecommunication switch that was damaged or requires a new data configuration. The invention is a computer containing a software program capable of manipulating and modifying data from source databases during the creation or modification of a new database.

Abstract: An optical adapter 100 includes a pair of cylindrical ferrules 121, 122, each containing an optical fiber disposed along its central axis 101-101. The ferrules are aligned with their central axes being collinear. Moreover, the ferrules are captured within a plastic housing that comprises a plug member 110 and a jack member 140. These members interlock with each other to form an adapter that can be used, for example, for attenuating an optical signal or for interconnecting two ferrules having different diameters. Preferably, the ferrules are identical to each other. Each ferrule includes an optical fiber that is disposed in a bore, which extend s along the central axis of the ferrule between its opposite ends, and each ferrule has an end face 126 that is angled at about 82 degrees with respect to the central axis.