Abstract: A junction field effect transistor, specifically a static induction transistor. Prior to metallization a thin layer of germanium is placed over the exposed silicon of the source and gate regions. The germanium is intermixed with the underlying silicon to form a germanium-silicon composite. A rapid thermal anneal is performed to recrystallize the germanium-silicon composite. Alternatively, a single crystal epitaxial layer may be deposited on the silicon. Conventional metallization procedures are employed to produce ohmic source and gate contact members to the germanium-silicon composite or the epitaxial germanium of the source and gate regions. By virtue of the reduced bandgap provided by the presence of the germanium, the contact resistance of the device is reduced.

Abstract: A predictive access-control and routing system for a telecommunications network operating in uncertain environments and capble of handling heterogeneous traffic. The system is a real-time, state-dependent network traffic control system in which the control strategy is a function of both real-time congestion levels and real-time traffic profiles. At specific time epochs, the system, using real-time measurements of source-destination arrival dates and trunk group link occupancies, generates predictions of all network trunk group occupancy levels for the next epoch as a function of routing and access control. It then minimizes a projected cost function, such as blocking, to generate a traffic control policy to be implemented during the next time interval.

Abstract: A power amplifier circuit utilizes vertical power transistors, such as static induction transistors, field effect transistors, or bipolar junction transistors, in a configuration where an ungrounded terminal serves as a common node while a separate reference terminal is connected directly to ground. A transformer of appropriate bandwidth couples an rf input signal to the input terminals of the transistor such that the input terminals are floating relative to ground. The novel amplifier circuit establishes separate electrical paths between the common terminal and the input circuit and between the common terminal and the output circuit. Thus, negative feedback is not present in the common lead, thereby improving gain, power output, and efficiency. Moreover, the circuit, in either a BJT, FET, or SIT configuration, can be fabricated on thinned semiconductor chips to form a transistor package in which the chips are bonded directly to the package heatsink.

Abstract: Glass compositions for high efficiency erbium.sup.3+ -doped optical fiber lasers, amplifiers and superluminescent sources are optimized for pumping by high power solid state lasers in the vicinity of 800 nm to provide amplified signals in wavelengths between 1.5 and 1.7 microns, a principal telecommunications window. A number of suitable host glasses for doping with erbium 3+ are identified wherein the excited state absorption/ground state absorption intensity ratio calculated at 800 nm is 1.00 or less.

Abstract: A package for an optoelectronic array device having an array of n active elements optically coupled to an array of n single-mode optical fibers which connect said optoelectronic array to an external device includes a housing having a solderable substrate to which the array device is secured, a graded index lens also secured to said array at a distance calculated to provide a known magnification of light beams emanating from said array and n uptapered single-mode optical fibers actively aligned to said magnified light beams to achieve optimal optical coupling to said optoelectronic array. The package optionally includes a multifiber holder having precisely calculated spacing based on the spacing of said active elements which are usually semiconductor lasers and the magnification of said lens. For a two-dimensional surface array, the package includes a mandrel to position the uptapered optical fibers.

Abstract: A true n-by-n optical crosspoint matrix switch has n optical fiber outputs each carrying the same light that entered the switch at one of n fiber inputs, maintaining the full optical spectral characteristics although the polarization states may be modified. A mounting plate on a patch panel has an n-by-n array of connection adapters in n rows and no columns. An electromechanical positioning mechanism is utilized to position n input fibers along one row to any of n adapter positions each in a different column on a first side of said plate, and n output fibers along one column to any one of n adapter positions, each in a different row on a second side of said plate. Any input fiber can be connected to any output fiber and none of the adapters are shared by more than one input or one output connector.

Abstract: A localized cooling method allows the sequential alignment and soldering of one optical fiber at a time to a semiconductor package, while previously aligned and soldered optical fibers are held fixed. This method utilizes the mechanical property of a sharp melting point eutectic alloy solder or a pure metal solder for the fiber connections and is effective for multi-fiber optoelectronic packages demanding stability and high precision. A package design for optoelectronic components requiring multi-fiber alignment incorporates this feature of localized cooling internally. The localized cooling method and the novel package utilizing this method internally make it possible to eliminate the tilted angle optical fiber alignment problem by mounting tilted facet optical amplifier components at a predetermined offset angle.

Abstract: An integrated optical intensity modulator is constructed by cascading individual waveguide directional coupler sections, each having a primary and secondary waveguide and a pair of uniform electrodes. A modulator normally operating in an OFF state has a bar-type structure such that the primary waveguides form one complete and straight waveguide. An input optical signal applied to this modulator propagates straight through the device. Another modulator structure normally operating in an ON state has a cross-type configuration which operates such that the coupled signal from one coupler section serves as the input signal for a next section. Each modulator is driven from its normal state into an opposite state by applying a voltage to the electrodes for inducing changes in the refractive index profile. A plurality of the optical modulators are fabricated in parallel on an integrated optical wafer to form a high-density optical gate array.

Abstract: A hybrid design for rectangularly configured integrated optical matrix switches uses both 2.times.2 optical changeover switches and 2.times.2 optical shift switches to achieve significant reduction of crosstalk accumulation for a strictly nonblocking switch architecture. The 2.times.2 optical shift switches are novel two-stage switches which allow two connection paths to bypass each other with very little crosstalk in the crossover state. A crossbar matrix switch uses 2n 2.times.2 optical changeover switches in the outer stages and n.sup.2 -2n optical shift switches in the intermediate stages.

Abstract: A 1.times.2 integrated optical switch with a high extinction ratio is obtained from the monolithic integration of three integrated waveguide couplers. The waveguide couplers are designed such that the output of the first waveguide coupler is directly coupled to the input of the other two integrated waveguide couplers by an integrated waveguide. Thus, the switch has two cascaded integrated waveguide couplers along each path from the single input to each of the two outputs. Only two pairs of electrodes are required by this design. The extinction ratio of this switch is the sum of the extinction ratios along an input-output path. Since integrated waveguide couplers are bidirectional, this switch can be used as a 2.times.1 switch by reversing the input and outputs.

Abstract: Split-screen video displays are presented at a plurality of different sites for a video teleconference. Video cameras are focused respectively upon the conferees directly, and centrally. The displays at each site show the conferees at remote sites. The positioning of the conferees at different sites on a display is achieved electronically, as by delays of a half a line and/or delays of half a field, rather than by panning or tilting of a camera.