Abstract: Fabrication of an optoelectronic device is enhanced by using a focused ion beam to prepare one or more of the device's facet surfaces. In particular, a facet may be oriented at a nearly arbitrary angled with respect to the waveguide within the device by controlling the orientation between the focused ion beam source and the device waveguide. Such facets are useful as antireflection and refractive beamsteering surfaces.

Abstract: In a laser such as a mode-locked or Q-switched laser, one of the resonator reflectors comprises a switchable Faraday rotator mirror coupled to a switchable magnetic field source. The operation of the laser is therefore controlled by the application of the magnetic field to the Faraday rotator device. When no magnetic field is applied, the device behaves as an isolator and thereby breaks the signal path between the resonator reflectors. When a saturation magnetic field is applied, the reflectors, disposed on opposite sides of the optical gain medium, thereby form a cavity such that lasing will occur. The device may be formed of discrete components or fabricated as an integrated optical device.

Abstract: A variable optical attenuator comprises a Faraday rotator including a ferromagnetic garnet film disposed input/output single mode optical signal paths. A collimating/lensing arrangement is used to focus the optical signal between the input/output signal paths and the ferromagnetic garnet film. The ferromagnetic material exhibits multiple types of magnetic domain such that an optical signal will experience ±rotation as its passes through the film. A 90° garnet film thus provides ±90° rotation, resulting in a fill 180° directional difference between the optical signal components. The amplitudes of these signals will thus cancel, providing an essential “full” attenuation of the optical signal. The application and adjustment of a magnetic field to the garnet film controls the strength (i.e.

Abstract: A fixture and method for providing accurate and repeatable alignment and attachment of a semiconductor wafer to a corner cube exposure fixture includes a vacuum-assisted wafer holder of rectangular shape. The wafer holder is first placed upon an L-shaped loading fixture so that a wafer may be positioned against the front surface of the holder and manipulated until the pair of wafer flats abut each leg of the L-shaped fixture. When so aligned, a vacuum is applied to secure the attachment and alignment of the wafer vis-à-vis the wafer holder. The wafer holder is thereafter inserted in a corner cube exposure fixture, where the fixture is formed to include a right-angle bracket with alignment features formed in one leg of the angle. The wafer holder also includes alignment features in its bottom surface, where these features are formed to mate with the bracket upon attachment.

Abstract: An optical mirror switch is formed by utilizing a pair of walk-off devices separated by a polarization switch. A first signal port is coupled to the first walk-off device and a second signal port is coupled to the second walk-off device. A reflective surface is also disposed beyond the output of the second walk-off device. In a first, “pass through” state of the switch, an optical signal applied as an input at the first signal port will propagate through the switch and exit at the second signal port. In a second, “reflective” state of the switch, an optical signal applied as an input at the first signal port will propagate through the switch, impinge the reflective surface and be re-directed back through the switch and exit through the first port. The “state” of the switch is controlled by the “state” of the polarization switch (which either exchanges the polarization states of the orthogonal components passing through, or maintains them).

Abstract: A BIST circuit for use with a read channel device is disclosed that utilizes internally generated clock and control signals to control a test sequence. A linear feedback shift register is used as the signature analysis register. The test signature accumulation process is controlled by clock and control signals internal to the read charnel device that are associated with the normal operation of the read channel device.

Abstract: A CMOS gate structure comprises a multilayered polysilicon structure and a deposited silicide layer, with a nitridized silicide barrier layer formed therebetween. The multilayered polysilicon will exhibit a relatively large grain size and uniform structure. The deposited silicide layer is annealed to mimic the polysilicon grain size and structure. The combination of the tailored grain structure with the intermediate barrier layer results in a gate structure that is essentially impervious to subsequent dopant diffusions.

Abstract: A silicon optical bench arrangement is used to provide for proper angular orientation between various components of an optical subassembly. A set of "optical stops" comprising alignment spheres held in pyramidal detents are formed in predetermined locations across the surface of an optical substrate. The separate optical components are positioned adjacent to the optical stops and subsequently held in place by bonding or other attachment means. By properly positioning the optical stops with respect to one another, any desired orientation between the optical components can be achieved.

Abstract: An outdoor battery cabinet is formed to include a cooling system to extend the life of the housed batteries. The cooling system comprises a ventilation system including an air intake unit, an exhaust unit and a thermostat control. The interior surface of the cabinet is covered with a layer of insulative material. The ventilation system is configured to turn "on" when the outdoor temperature drops below the interior cabinet temperature, thereby cooling the housed batteries. Once the outdoor temperature rises above the cabinet temperature, the ventilation system is turned "off" and the insulation in the cabinet functions to maintain the cooler ambient temperature within the cabinet. To minimize the effects of wind forcing air through the ventilation openings, the intake and exhaust louvers are located on the same side of the cabinet.

Abstract: An optical multiplexer is formed that overcomes the polarization dependence of conventional DWDM routers and is also significantly smaller than prior art routers. A reflective router is formed that utilizes one-half of a star coupler, with a reflective surface formed along the planar face of the coupler so as to form a "folded" arrangement. First and second waveguide arrays are coupled to opposing quadrants of the folded coupler, with the reflective surface providing the coupling therebetween. A quarter wave plate (or Faraday rotator) and reflective surface are disposed at the output of the second waveguide array and are used to provide a TE/TM mode conversion to the optical signals exiting the second array (thereby canceling out any polarization-dependent effects). The reflective surface beyond the quarter wave plate re-directs the optical signal back through the second waveguide array. The signal will then again reflect through the folded coupler and exit the multiplexer through the first waveguide array.

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: A method and apparatus for essentially eliminating ESD damage to integrated circuits being subjected to thermal shock testing includes the utilization of a static dissipative plastic carrier capable of withstanding high temperatures (e.g., 155.degree. C.) and exhibiting a surface resistivity in the range of, for example, 10.sup.10 -10.sup.12 .omega./.quadrature.. Such a static dissipative plastic support structure will therefore eliminate static buildup during integrated circuit testing and prevent ESD damage to the circuits.

Abstract: An incrementally continuous cleaving system allows for sequential flow of "material-to-be-cleaved" through a cleaving apparatus. In particular, a continuous feed tape membrane is used to support sequentially loaded optical bars (or, perhaps, wafers) that are then transported into a cleaving apparatus. The tape is advanced in small increments so that individual cleaving operations are performed at each scribe mark location on the top surface of the optical material. A vacuum pen (assisted by a detach pin) is then used to remove the cleaved section from the cleaving system. A conventional pick-and-place device may be used in the first instance to continuously load the bars (or wafers) onto the tape membrane.

Abstract: An arrangement for reducing power consumption in a flash A/D converter uses a predictor module to compute the "next" digital output value (i.e., s(n+1)) and then uses this value to regulate the number of individual comparators required to perform an accurate conversion. The predictor module is disposed as a feedback element between the converter output and the comparator array. Based upon the prediction, the module transmits a control signal to the comparator array, turning "on" and "off" subsets of the comparators forming the array. By maintaining a large number of the comparators in the "off" state (usually, only half of the comparators need to be enabled), a significant power savings can be realized.

Abstract: An optical monitoring system for III-V integrated circuit wafers utilizes an optical transmitter/receiver assembly formed in the wafer at an early stage in the fabrication process. The optical transmitter is then activated and the optical output signal is monitored during subsequent processing steps, such as ion implantation and layer deposition to assess the quality of the process. In one embodiment, the monitoring system is useful as an endpoint detection process.

Abstract: An optical fiber ferrule assembly is disclosed which comprises an inner sleeve (of a metallic material, for example) including a necked-down portion for securing the fiber, and an outer housing (of a plastic material, for example) formed as a cylindrical member through which the sleeve may be inserted. A washer may be attached to a flanged end portion of the sleeve and subsequently laser welded to an associated optical submount.

Abstract: A method is disclosed for forming a self-aligned optical subassembly for supporting an optical fiber and associated optical component(s). In particular, sequential masking layer/silicon substrate etch operations are performed so as to etch, in series, the largest opening first and the narrowest opening last. By following this procedure, axial alignment between tandem grooves is maintained.

Abstract: An arrangement is disclosed for determining a byte error rate (ByER) of a received digital signal. In particular, a local byte clock signal is generated and a complement of the received signal (or clock signal) is compared to the clock signal (or received signal). When both are the same logic value, as determined by a series of logic gates, an error is deemed to have occurred. A counter is utilized to track a number of occurrences N over a predetermined period of time T.

Abstract: A cascaded distortion compensation arrangement is disclosed which utilizes a plurality of pre-distortion components disposed in a series arrangement at the input to the transmitter and a plurality of post-distortion components disposed in a series arrangement at the output of the receiver. The various components may be modified, added and/or deleted to provide an arrangement suitable for the particular system.

Abstract: A tin-rich gold-tin solder is disclosed which is particularly advantageous for self-aligning applications. When utilized with gold-plated bond locations, the out-diffusion of tin from the solder during heating functions to shift the composition of the remaining solder closer to the eutectic value, thus preserving the liquid state of the solder and improving its reflow quality with respect to conventional eutectic solders.