Abstract: A segmented plasma excitation and recombination (SPER) device is employed in a deposition scheme in which the plasma generated in the gap between adjacent electrodes is formed into a beam of ions/atoms by flowing a background gas through the gap. The beam strikes a workpiece and deposits a layer of the vaporized electrode material thereon. Also described are techniques where the ions react with workpiece or the background gas to form a layer, as well as where the ions bombard the workpiece to etch away a layer.

Abstract: Semiconductor lasers and LEDs are described in which the pumping current is constrained to flow from a relatively narrow upper channel formed by a V-groove, which extends to a depth short of the active region, through a relatively wider lower channel bounded by high resistivity regions, which extend from at least that depth into or through the active region. Also described are devices in which the V-groove is refilled with semiconductor material.

Abstract: Circuits for selectively operating redundant light sources (lasers or LEDs) in lightwave communication systems are described.

Abstract: A ring cavity laser is disclosed wherein a Rhodamine 6G dye stream is used as the gain medium, and a saturable absorber stream is positioned in the ring cavity at a point such that the time difference between pulses arriving at the gain stream is not small compared to the recovery time of the gain medium. The saturable absorber is DODCI dissolved in ethylene glycol passed through a specially constructed nozzle that creates a dye stream having a thickness of about 10 microns in the optical cavity. As a result of this thin saturable absorber, the two counterpropagating pulses that collide in the saturable absorber are caused to interact in a way that results in a decrease of the pulse duration and an equalization of the pulse intensities.

Abstract: A superconductive circuit is described for diverting bias current to an output line in response to magnetic field control means. A first plurality of branches containing magnetically switchable Josephson junction gates are connected in parallel, and a second plurality of the same gates, less than or equal in number to the first plurality, are actuated essentially simultaneously by the control means. As a consequence, high-gain, high-speed operation is made possible.

Abstract: The reverse leakage current of InGaAs diodes, in particular the dark current of In.sub.0.53 Ga.sub.0.47 As photodiodes, is reduced by a treatment in a 1:1:X solution of H.sub.2 O.sub.2 :H.sub.2 SO.sub.4 :H.sub.2 O where 10.ltoreq..times..ltoreq.100 approximately.

Abstract: An electrical signal, such as a high current pulse, is applied to a series of two or more conducting strips (101-110) installed in series in a laser cavity (150, 151) containing either a buffer gas or a vacuum. The strips are separated by small gaps. When the electrical signal is applied to the strips, plasmas (141-149) are formed in the gap regions. The plasmas are comprised of ions from the strip material. Once formed, these plasmas expand hemispherically, cool and recombine to generate radiation. The composition of the plasmas depends on the strip material, the electric field in the gaps, the gap size and the background gas type and pressure.

Abstract: Disclosed are double heterostructure junction lasers and incoherent LEDs in which the active region comprising Al.sub.z Ga.sub.1-z As.sub.1-y Sb.sub.y 0.001.ltoreq.y.ltoreq.0.02 and in which the cladding layers comprise Al.sub.x Ga.sub.1-x As, (x-z).gtoreq.0.20. Long lifetime lasers operating at wavelengths in the vicinity of 0.87-0.92 .mu.m are realized. Visible wavelength lasers and LEDs are also discussed.

Abstract: The invention is a reduced noise avalanche photodetector. The detector comprises a p-type region, an n-type region, and a graded bandgap avalanche region situated between the p- and n-type regions. Radiation to be detected is absorbed in one of the p-type and n-type regions and charge carriers are generated in response thereto.When the device is under a reverse bias, one type of photogenerated charge carrier is injected by diffusion into the graded bandgap region and initiates an avalanche discharge therein. The carrier type initiating the discharge moves toward a region of decreasing bandgap energy, while the other type of charge carrier moves toward a region of increasing bandgap energy, thus resulting in a large difference between the ionization coefficients of the two types of charge carriers. The differing "quasi-electric" fields experienced by the two types of charge carriers also contributes to the difference between the ionization coefficients of the electrons and holes.

Abstract: A dual-wavelength light-emitting diode (10) is disclosed wherein at least two quaternary layers (102 and 104) are epitaxially grown on indium phosphide substrate (100) and a top indium phosphide layer (105) of the opposite conductivity type is grown to establish a junction (121) in the topmost quaternary layer. An isolation channel (106) cuts through the epitaxial layers and divides the device into two separate regions. A dopant is diffused into one of the regions in order to establish a pn junction (122) in the bottom quaternary layer. Independent electrical contacts (107 and 108) bonded to the top indium phosphide layer in each of the regions establish an electrical connection to pn junctions in each of the two separate regions. The device can be effectively heat sinked by mounting the epitaxial layer side of the substrate to a beryllium oxide heat sink (200) onto which gold bonding pads (201 and 202) have been plated.

Abstract: Described is a DC powered flip-flop logic or memory element (i.e., circuit) which comprises two Josephson junction gates J.sub.1 and J.sub.2 which operate individually in the latching mode. In one logic state, the gate J.sub.1 is at V.sub.1 =O while J.sub.2 is at V.sub.2 .noteq.O. In the other logic state, the roles of the two junctions are reversed. The two junctions are interconnected by a passive network such that the switching of J.sub.2, say, from V.sub.2 =O to V.sub.2 .noteq.O induces a current-voltage transient on J.sub.1 which returns it to V.sub.1 =O, and conversely.

Abstract: A metal layer is formed on a surface of a Group III-V compound semiconductor by placing the surface in contact with a metal-containing solution and directing laser radiation through the solution. The radiation has a wavelength which is absorbed in the surface, thereby thermally inducing a chemical reaction between the surface and the solution and causing metal from the solution to be deposited on the surface. Specific examples of the deposition of Pt, Au and Zn on InP and GaAs are described.

Abstract: An optical polarizer is described in which a propagation layer (14) is covered with a dielectric buffer layer (16) and a metal layer (18). The thickness of the buffer layer is chosen so as to increase the attenuation of TM modes of radiation in the waveguide relative to TE modes. In accordance with the invention, additional discrimination between TM and TE modes is achieved by segmenting the metal layer into a plurality of tandem sections (18.1, 18.2, 18.3), thereby increasing the mode coupling loss for TM modes. A GaAs-AlGaAs rib waveguide polarizer is specifically described.

Abstract: This invention relates to granular metal and metal oxide superconducting films formed by ion beam sputter deposition. Illustratively, the films comprise irregularly shaped, randomly oriented, small lead grains interspersed in an insulating lead oxide matrix. The films are hillock-resistant when subjected to thermal cycling and exhibit unusual Josephson-type switching characteristics. Depending on the oxygen content, a film may behave in a manner similar to that of a plurality of series connected Josephson junctions, or the film may have a voltage difference in a direction parallel to a major surface of the film that is capable of being switched from zero voltage difference to a finite voltage difference in response to a current larger than the critical current.

Abstract: A unipolar, rectifying semiconductor device is described. Rectification is produced by an asymmetric potential barrier created by a sawtooth-shaped composition profile of Al.sub.x Ga.sub.1-x As between layers of n-type GaAs. Single and multiple barriers, as well as doped and undoped barriers, show rectification. Also described is the incorporation of this type of device in an infrared detector, a hot electron transistor and mixer diodes.

Abstract: An acoustic superlattice of alternating layers of different acoustic impedance is disclosed as a filter for high frequency phonons. Applications discussed include spectrometers, acoustic imaging apparatus, and cavity resonators.

Abstract: The transfer characteristic of nonhysteretic Josephson junction gates (G) is sharpened and desired switching behavior free from resetting requirements is achieved by a positive feedback scheme (FIGS. 5, 8-9) in which the gate is made to be responsive to current flow in the output line (20). Specific applications to three-junction interferometers (FIG. 5) are described as are various means for rendering the gate responsive to the output, i.e., magnetically coupling the output line to the gate (FIGS. 5, 8), adding a portion of the output current to the control line (FIG. 9), and injecting a portion of the output current directly into the gate (FIG. 10).

Abstract: This invention is a semiconductor junction laser which operates in a transverse mode, other than the fundamental mode, parallel to the p-n junction. An undesired transverse mode parallel to the p-n junction may be suppressed by introducing a lossy region within the laser where this mode has at least one of its maxima. The zero order transverse mode parallel to the p-n junction may be suppressed in a double heterostructure stripe geometry laser by introducing an optically or electrically lossy region in the current flow path of the laser where the zero order mode has its maximum. This double heterostructure stripe geometry laser operates linearly with respect to current in the first order transverse mode parallel to the p-n junction.

Abstract: The invention is a method and apparatus for growing group III-V semiconductor layers by molecular beam deposition in which a gaseous source is used to form a molecular beam comprising M.sub.2 or M.sub.4 molecules, where M is a group V element. Arsine and phosphine may be decomposed in a high temperature leak-source to provide As.sub.2 and P.sub.2 molecular beams for molecular beam epitaxy of group III-V semiconductors such as GaAs and InP.

Abstract: A feedback control arrangement in a fiber optic lightwave transmitter compensates for changes in the average power coupled from a laser into a fiber due to certain displacements of the fiber relative to the laser. The arrangement includes a laser (10) and an optical fiber (28) having a beveled end face (30) oriented to couple a major portion (13) of the laser beam into the fiber. The position of the fiber relative to the beam axis (12) is sensed by a pair of photodetectors (20, 22) positioned on opposite sides of the beam axis so as to receive other portions of the beam (15, 17) not coupled into the fiber. A feedback circuit (24) is selectively responsive to the smaller of the photodetector outputs for controlling the drive current to the laser so as to maintain the average power coupled into the fiber essentially constant.