Abstract: An improved process for fabricating photonic circuits is disclosed. The inventive process starts with a growth of a base wafer comprising a stack of epitaxial layers of various materials. At least a portion of each of the material layers will ultimately be a functioning part of any of a number of devices which will form the PIC or will serve a role in at least one of the fabrication processing steps. Specific inventive processing steps are addressed to (1) interconnecting passive waveguides, active devices, and grating filtering regions without the substantial optical discontinuities which appear in the prior art, and (2) etching continuous waveguide mesas to different depths in different regions of the PIC so as to optimize the performance of each PIC device.

Abstract: Apparatus and method are disclosed for controlling the tone spacing (2.omega..sub.d) and output power level in an FSK lightwave transmitter. An arrangement is utilized which splits a tapped-off portion of the output data stream into two essentially equal components. A first component is then delayed and scrambled (polarization state) with respect to the second component. Self-heterodyning of the two signals results in forming a signal at the beat frequency, or tone spacing value. By comparing this beat frequency with a predetermined tone spacing value, adjustments may be made to the transmitter to maintain the desired tone spacing value. The self-heterodyned signal will also contain a component indicative of the data signal power level and may be utilized to adjust the transmitting device so as to maintain a constant power.

Abstract: A diversity receiving system for a differential phase shift keyed digital signal having symbols occurring in successive time periods comprises at least one antenna and a plurality of receiving branches. Each receive branch operates on a different version of the digital signal and detects different type prescribed components of the phase difference between successive symbols of the branch version. A detected prescribed component of the phase difference of each type is formed for each successive time period by processing the same type detected prescribed phase difference component signals from the receive branches.

Abstract: An integrated circuit, and a method for laying out and creating the integrated circuit, which contains large circuit blocks placed at any desired location on a chip, with the rest of the circuitry placed in the remaining non-rectangular area on the chip. The layout takes account of connections from within the circuit area to connection points external to the area. The procedure for the automatic layout proceeds in two steps. The first step is global partitioning and placement, and the second is detailed placement. The global partitioning performs the logical partitioning of the cells into clusters to be placed among and between the macro cells and the external terminals, with each cluster being eventually laid-out in a rectangular area. The second step involves the detailed placement of cells within the rectangular areas. Partitioning is accomplished by an iterative process, where at each iterative step the non-rectangular area is divided into two parts of approximately equal size.

Abstract: An article comprised of a body having a conductor pattern on at least one non-planar and non-flexible surface thereof. The article is prepared by using a three-dimensional mask having an interior surface which is a mirror image replica of the surface of the body on which the conductors are to be formed. The surface of the body is provided with material which is capable of initiating conductor formation. The interior surface of the mask then is placed over the body and in substantial registry therewith. The mask and the body then are exposed to radiation or moving material to delineate the conductor pattern. Subsequently, the mask is removed and conductors are formed.

Abstract: Users of an on-line documentation facility in a computer system are provided with the capability of specifying modifications to be made to the documentation that would otherwise be provided by the system.

Abstract: Each multiply-accumulate device, in an adaptive equalizer, multiplies each input signal sample by an associated coefficient in an ensemble, stores the result and periodically outputs the accumulated results as the equalized input signal. A rotating coefficient register in the adaptive equalizer successively associates each coefficient in the ensemble with a different multiply-accumulate device. Coefficient update circuitry is also provided which periodically updates the coefficients in the ensemble so as to optimize equalizer performance.

Abstract: An improved decision-directed control circuit is disclosed which supplies adjustments to adaptive circuitry in a communications system. The improvement is achieved by only supplying adjustments when there is a high probability that the adjustment is correct. In the disclosed embodiments, this high probability equates, at a minimum, to times when the adaptive circuit output has an amplitude which lies outside of a range extending from the largest to the smallest value of the digital signal. This adjustment approach can be used to adjust a variety of adaptive circuits including transversal equalizers, timing recovery circuits, cross-polarization cancellers and carrier recovery circuits.

Abstract: A technique is disclosed for equalizing an incoming signal including quadrature-related carrier signals by forming the product of the incoming signal at at least one prescribed time and only one real-valued coefficient associated with each time. In one embodiment of the present invention, the equalized incoming signal is demodulated into a first pair of component signals. At least one of these component signals is then used to generate each coefficient. In another embodiment of the present invention, each coefficient is generated in response to at least one of the component signals in the first pair along with a second pair of component signals which are formed by demodulating the incoming signal. This technique can be advantageously adapted to incorporate a number of coefficient updating algorithms and is suitable for use in a number of modulation formats.

Abstract: A technique is presented for simplifying the recovery of two synchronous data signals having a common symbol rate after each signal has respectively modulated a different one of a pair of quadrature-related carrier signals. In the transmitter, the data signal which modulates one of the quadrature-related carrier signals is delayed relative to the data signal which modulates the other quadrature-related carrier signal. This delay is related to an IF frequency chosen at the receiver. After passing through a noisy transmission channel, the quadrature-related carrier signals are coupled in the receiver to a serial combination of an equalizer and analog-to-digital converter. This combination outputs multiple, substantially distortion-free samples of the data signals each symbol interval. The two data signals are then recovered by selecting a subset of the samples provided each symbol interval.

Abstract: Disclosed are methods that result in substantial improvement of silicon-on-insulator (SOI) device manufacture. We have discovered that carbon can be advantageously used as a wetting agent in the melting-recrystallization (MR) method of producing SOI wafers. We have also found that contacting the wafer (typically subsequent to the formation thereon of a poly-Si layer on a SiO.sub.2 layer but prior to the completion of formation of a SiO.sub.2 cap layer on the poly-Si layer) with an atmosphere that comprises a wetting agent-containing molecular species (e.g., CH.sub.4, NH.sub.3), with the wafer at an appropriate elevated (e.g., 500.degree.-900.degree. C.) temperature, can reliably result in recrystallized Si films of high quality. Furthermore, we have discovered the existence of a previously unknown parameter regime (low thermal gradient across the resolidification front, typically no more than about 4.degree. C./mm) for the MR process that can result in a highly perfect (.chi.

Abstract: A second order gradient microphone with unidirectional sensitivity pattern is obtained by housing each of two commerically available first order gradient microphones centrally within a baffle. The baffles have flat surfaces, are preferably square or circular and have parallel surfaces the two baffles being parallel to each other. The rotational axes of the microphones are arranged to coincide. The output signal from one of the microphones is subtracted from the delayed signal output of the other.

Abstract: Disclosed is a connector module for making electrical contact between two essentially parallel boards which include contact pads on the edges. The connector includes at least one conductive member adapted to extend from a pad on one board to a corresponding pad on the other board. The connector also includes an insulating support member formed to extend from the top of one board, around the edge of that board, and to the top of the other board. This support member fixes the distance between the boards, permits the conductive members to make electrical contact for test purposes prior to clamping, and provides an appropriate clamping force for the connection to the first board.

Abstract: A technique for digitally synthesizing the amplitude modulation of one or more carrier signals with a random digital data signal is disclosed. Pursuant to the present invention, a memory unit is addressed by a plurality of binary coded digital symbols in the data signal. For each address, at least two digital representations are read out. Each representation corresponds to a different sample of the carrier signals which has been amplitude modulated by a composite of the spectrally shaped data signal. The disclosed technique can be adapted to synthesize a variety of modulation formats, and can provide compensation for fixed in-rail and cross-rail distortions.

Abstract: This is an improved resistive line battery feed circuit where the improvement consists in establishing a balanced stable power point using an opamp and capacitive input and feeding the AC output to both lines of the tip and ring circuit via opamps and a hybrid for injecting current. In this manner longitudinal balance is maintained. Current is added to the line circuit by a modulated DC current source.

Abstract: A terrestrial radio system which utilizes spot beams, time division multiple access and frequency reuse to provide communications services from a base station to remote customers within a system service region. The base station advantageously is arranged with multistage switching so as to permit the respective sharing of radio transmitters and receivers over larger number of antenna transmitting and receiving ports.

Abstract: An optical package includes a two-piece fiber subassembly which allows for separate axial and radial alignment of the fiber to the active optical device. The subassembly consists of an inner ferrule encasing the fiber and an outer sleeve which holds the ferrule. The ferrule is moved axially within the sleeve to perfect the axial alignment of the fiber and the device. The sleeve includes a number of openings around its circumference to expose the ferrule. Once axial alignment is achieved, the outer sleeve is attached to the ferrule through these openings to fix the axial alignment.

Abstract: A high voltage silicon device with a resistive field shield comprising semi-insulating silicon nitride (sin-SiN). The N/Si ratio is controlled to provide the resistive field shield with the desired conductivity. This resistive field shield material may also serve as an outer protection layer for the device.

Abstract: A new sub-micron bipolar transistor structure is proposed which utilizes narrow horizontal conducting layers between the edges of the active areas and the associated metal contacts. This structure allows the formation of a completely vertical transistor structure and eliminates the need for the extended buried collector and collector reach-through diffusion regions.