Abstract: Presented is a dual wavelength structure wherein two edge-emitting devices are bonded with p-regions adjacent. The bonding medium is a conductive compound that forms a common electrode between the devices. Each device is separately addressable. Efficient coupling of emitted light into a single fiber is accomplished by restricting the vertical and horizontal separation of the light emitting stripes.

Abstract: Disclosed is a method of producing a suitable array of semiconductor chips or other objects for visual inspection. Semiconductor chips on the order of a few hundred microns on each side are placed onto a mesh screen in a container, then submersed in deionized water, so that the chips begin to float and the fluid never covers the upper surfaces of the chips. Gently swirling the fluid causes the chips to orient in the center of the container. Continued swirling aligns the chips into an orderly array of rows and columns.

Abstract: Apparatus including a semiconductor laser source and means for stabilizing the frequency of the laser. A feedback signal is provided by means such as a Fabry-Perot interferometer, which signal is coupled simultaneously to two feedback loops. One loop provides high frequency control of the drive current while the other loop provides low frequency control of the laser temperature.

Abstract: A read/write system is disclosed for optical disc apparatus. The light source is removed from the head and optically coupled to the disc by a single-mode fiber which acts as a spatial filter. Adverse effects on the light source due to reflection from the disc are avoided by making the fiber length greater than one-half the coherence length of the source. A sparing switch and combiner component may be included in the system. An array of discrete light sources, each coupled to an associated fiber, may also be employed for multiple track accessing.

Abstract: An m.times.n optical switch is formed on a semiconductor substrate. Grooves are etched at the edges of the substrate to accommodate input and output optical fibers so that the output fibers are placed orthogonal to the light paths of the input fibers. An array of photodetectors is provided at an edge opposite to that of the input fibers to receive the input signals. At each crosspoint defined by the input and output fibers is an electromechanically actuated mirror which in one state permits passage of light from its associated input fiber, and in another state deflects the light to its associated output fiber.

Abstract: Disclosed is an optical device producing single mode laser emission. The device includes a semiconductor laser which would normally emit a number of closely spaced longitudinal modes and a filter which receives light from the laser active layer and reflects light back to the active layer. The filter includes at least one thin, optically absorbing layer, a dielectric layer, and a reflecting layer. The thickness and refractive indices of the layers are such that the filter reflectivity has a number of narrow maxima, but only one which lies within the gain bandwidth of the laser. The width of the peak and the background amplitude between peaks is such that only a single longitudinal mode of the laser is allowed to oscillate.

Abstract: Disclosed is a high resolution optical scanning method and apparatus. Light from a source, such as a laser, is focused onto a flat, rotating mirror. The reflected light is made incident upon a stationary elliptical mirror such that the real or virtual source is at one focus of the ellipse and the points on the line to be scanned are at the other focus along the lateral dimension of the mirror. A large useful angle of rotation is thereby achieved for each line scan.

Abstract: Disclosed is an electroacoustic transducer, such as a microphone, which may be integrated into a semiconductor chip and a method of fabrication. The semiconductor is etched to produce a membrane having a sufficiently small thickness and an area so as to vibrate at audio frequencies. Electrodes are provided in relation to the membrane so that an electrical output signal can be derived from the audio frequencies, or vice versa, due to variable capacitance. Preferably, the sensitivity of the device is made to be an approximately linear function of sound pressure level to be compatible with amplification.

Abstract: Disclosed is a dual-gap protector wherein both gaps will break down essentially simultaneously when a pulse of either polarity having a sufficient magnitude appears. An annular electrode is provided in the housing so as to form parallel gaps with respective end electrodes. The electrodes include a surface coating of a photoemissive and/or thermionic material so that light emission or heat resulting from the breakdown of one gap will influence the breakdown of the other gap.

Abstract: Disclosed is an AC gas plasma display which provides the benefits of a planar display and permits a substantial separation of the write/erase and sustain function circuitry. First and second arrays of parallel electrodes (X.sub.1 -X.sub.3, Y.sub.1 -Y.sub.6) are disposed orthogonally on opposite surfaces within the gas envelope. One of the arrays includes a plurality of adjacent pairs of electrodes, e.g., Y.sub.3 and Y.sub.4, capable of sustaining glow discharges at the crosspoints of the two arrays. A desired area is illuminated or extinguished in a two-step sequence by applying appropriate pulses to selected electrodes in both arrays. For further separation of write/erase and sustain functions, one of the arrays can include a plurality of sets of three adjacent electrodes (Y.sub.1 ', Y.sub.2 ', Y.sub.3 ' of FIG. 10), with write/erase pulses applied to one of the electrodes and sustain pulses applied to the other two electrodes in the set.

Abstract: An optical device which diverts light from one transmission element (e.g. 21) to another (e.g., 22, 23 and 24) and a method of manufacture are disclosed. The device includes a pair of focusing elements (10 and 11) such as graded index of refraction lenses separated by a pair of at least partially reflecting elements (12 and 13). Optical transmission elements are placed adjacent to the surfaces (17 and 20) of the focusing elements opposite the reflecting elements. The reflecting elements are placed at an angle to each other and the transmission elements positioned to achieve efficient light coupling. The reflecting elements can then be fastened to each other by an appropriate adhesive (14).In specific embodiments, the device may function as a multiplexer/demultiplexer for light having three or more wavelengths, or as an asymmetric four-port coupler.

Abstract: A read/write system which reduces access time in optical disc apparatus is disclosed. The head includes an array of lenses which covers a substantial portion of the radius of the disc. Access of a particular disc track is achieved by deflection of the reading beam, rather than by any physical movement of the head. For read-out, the array focuses light reflected from the disc onto a corresponding array of photodetectors.

Abstract: Disclosed is means for driving a laser whereby a dc bias current is supplied to keep the laser normally above threshold, and a modulation current brings the laser below threshold when a pulse appears. In one embodiment, a feedback controlled bias current source (11) and modulation current source (15) are coupled to the p-side terminal of the laser (10) while a constant voltage source (27) is coupled to the n-side terminal of the laser in a way which results in subtraction of the modulation current from the dc bias current. This mode of operation essentially eliminates laser overshoot and more nearly equalizes rise and fall times of the light pulses.

Abstract: An electroacoustic transducer, primarily in the form of a capacitive microphone, for incorporation into a semiconductor substrate. The vibrating element comprises a largely nontensioned diaphragm, such as an epitaxial layer formed on the semiconductor substrate, so as to greatly reduce its mechanical stiffness. The substrate is etched away in the desired area to define the diaphragm and form an acoustic cavity. A continuous array of microscopic holes is formed in the backplate to cut down the lateral flow of air in the gap between capacitor electrodes. Narrow gaps made possible by the hole array allow low voltage diaphragm biasing. In at least one embodiment, the acoustic input can be provided through the air hole array. An acoustic port may be added to alter the frequency response of the device, and a back closure provided to act as a rear acoustic cavity and an EMI shield.

Abstract: A method for batch-contouring crystal plates for frequency adjustment is disclosed. A plurality of plates is secured to a compliant sheet and the sheet is attached to an applicator surface which includes a resilient pad. The plates are then abraded against another surface to produce contours on all the plates. The resilient pad provides spring loading to insure uniform pressure on all the plates.

Abstract: Disclosed is an electroacoustic transducer structure which can be formed in a semiconductor substrate and incorporated as part of an integrated circuit, and which provides a built-in dc bias for operation. An appropriate density of fixed charge is provided in an insulating layer adjacent to one of the electrodes in the gap between electrodes. Methods of manufacture are also disclosed including means for introducing the charge by contacting the insulating layer with a liquid medium, plasma charging, or by ion beam implanting into the layer.

Abstract: A method of producing patternable resistive regions in III-V compound semiconductor devices and a resulting device structure having improved current characteristics. III-V semiconductor substrates are irradiated with inert ions to produce a resistive region therein. At least one epitaxial layer is grown over the substrate while maintaining the resistive characteristics within the substrate. A second resistive region is then formed in at least the top epitaxial layer. This second resistive region is aligned with the first one in order to minimize current spread through the device.

Abstract: A method of fabricating field effect transistors which includes control of threshold potential by an ion implantation limited to the active channel area. The active channel area is defined by a photoresist pattern. Ions are implanted into the exposed area in a concentration to achieve a desired threshold. Appropriate metals are deposited over the channel area to form a gate electrode. The photoresist is lifted off leaving the gate electrode in position over the channel area. If desired, a layer of polysilicon can be included prior to resist formation and later removed by an etchant which does not attack the gate electrode.

Abstract: Disclosed is a method of soldering external leads to film circuits formed on insulating substrates. The leads, usually in the form of lead frames, are clipped onto the substrates and a flux is applied. The assemblies are then immersed into molten solder. As they are withdrawn from the solder, they pass through high-pressure hot gas jets which remove the excess solder.

Abstract: A package for wire-bonded semiconductor integrated circuit chips is disclosed. The chip is covered by a protective layer of material such as room temperature vulcanizing silicone rubber. The thickness of the layer is such that it covers a portion of the arched wires, thereby concentrating the stresses away from the wire-ball bond interfaces. The chip is encapsulated in a plastic material while providing an air gap between the plastic and protective layer.