Abstract: A star-coupler and a method for constructing the star-coupler employing injection molding technology are disclosed. The star-coupler may be constructed from a single injection molded block or a plurality of mating sections, and is supplied with a plurality of input ports and a plurality of output ports. Each input port as well as each output port is connected to at least one channel. The channels are filled with a fiber optical core material and the single block or mating sections are fabricated from fiber optical core material. Alternatively, a separate cladding material may be coated on the surfaces of the block or mating sections which define the channels. Optical signals are guided and confined by the core and cladding material from input ports to output ports along the channels.

Abstract: A fiber optic star-coupler with a biconical mixing element and method for inexpensively manufacturing the same are disclosed. The fiber optic star-coupler includes an input fiber optic bundle, an output fiber optic bundle and a biconical mixing element. Each of the bundles comprises a plurality of individual optical fibers. The biconical mixing element includes tapered regions and a central mixing zone to promote uniform mixing and equal distribution of optical energy among all of the optical fibers in the output fiber optic bundle. The biconical mixing element is provided with connectors at each of its two ends for coupling to other connectors, adaptors, and fiber optic bundles. Alternatively, the biconical mixing element may be formed by injection molding techniques. The optical fibers may be constructed from plastic or silica.

Abstract: A shadow-masking process for manufacturing low dark current photodetectors with low noise characteristics is disclosed. The process includes shadow-masking a semiconductor wafer by positioning a patterned shadow-mask on a surface of the wafer. The shadow-mask is patterned with, for example, circular openings or stripe openings. Layers, such as metallization layers to form metallic contacts or anti-reflection layers are deposited onto the wafer through the patterned openings in the shadow-masks. This shadow-masking process may be used in the production of any semiconductor device requiring patterned layers.

Abstract: A star-coupler and a method for constructing the star-coupler employing injection molding technology are disclosed. The star-coupler may be constructed from a single injection molded block or a plurality of mating sections, and is supplied with a plurality of input ports and a plurality of output ports. Each input port as well as each output port is connected to at least one channel. The channels are filled with a fiber optical core material and the single block or mating sections are fabricated from fiber optical core material. Alternatively, a separate cladding material may be coated on the surfaces of the block or mating sections which define the channels. Optical signals are guided and confined by the core and cladding material from input ports to output ports along the channels.

Abstract: Photodiodes (10) are fabricated in a single step diffusion process which exploits the characteristic of certain acceptors to form an anomalous diffusion profile (VI) including shallow and deep fronts (VIa and b) joined by an upwardly concave segment (VIc). By performing this type of diffusion into a low-doped n.sup.- -type body (12) with a carrier concentration (VII) below that of the concave segment, a p.sup.+ --p.sup.- junction (15) is formed at the depth of the concave segment and a p.sup.- --n.sup.- junction (17) is formed at a greater depth. The zone (16) between the junctions is at least partially depleted and forms the active region of a p.sup.+ --p.sup.- --n.sup.- photodiode. Specifically described are InP:Cd photodiodes.

Abstract: A single heterostructure light emitting device which provides high speed and high efficiency. The device includes adjacent n- and p- regions of a mixed-crystal III-V semiconductor such as GaAlAs. A lightly-doped wide bandgap injection layer is utilized to force recombination in the more heavily-doped adjacent region. The latter region also includes a graded bandgap which allows photon recycling for high efficiency.

Abstract: Photodiodes (10) are fabricated in a single step diffusion process which exploits the characteristic of certain acceptors to form an anomalous diffusion profile (VI) including shallow and deep fronts (VIa and b) joined by an upwardly concave segment (VIc). By performing this type of diffusion into a low-doped n.sup.- -type body (12) with a carrier concentration (VII) below that of the concave segment, a p.sup.+ -p.sup.- junction (15) is formed at the depth of the concave segment and a p.sup.- -n.sup.- junction (17) is formed at a greater depth. The zone (16) between the junctions is at least partially depleted and forms the active region of a p.sup.+ -p.sup.- -n.sup.- photodiode. Specifically described are InP:Cd photodiodes.

Abstract: A method of liquid phase epitaxy is disclosed for growing a plurality of different layers on each of a plurality of semiconductor wafers during a single heating cycle. Each of a series of melts, each corresponding to a layer to be grown, is divided, in succession, into aliquant portions and a remainder portion. Each aliquant portion is contacted by one or more wafers, and epitaxial growth occurs as the temperature is lowered. Provision of a remainder portion enables a two-phase melt, and a wafer contacts only one distinct melt at a time.After a growth step, the next successive melt likewise is separated into aliquant portions and a remainder portion, the wafers are removed from the preceding melt chambers and placed in contact with the newly formed aliquant portions, and growth of another layer ensues from another drop in temperature. The process is repeated for each melt provided.Apparatus for carrying out the method also is described.

Abstract: The occurrence of pyramidal protrusions on the surface of GaAs and GaAlAs p-n junction wafers produced by a multislice liquid phase epitaxy process is avoided by slow cooling to a specified quenching temperature or below. The pyramidal protrusions are constituted of the silicon which is the amphoteric dopant used in these semiconductors. Pyramids are not formed if the epitaxial reactor is cooled at a rate of 1.degree. Celsius to 3.degree. Celsius per minute to a temperature less than about 140.degree. Celsius before the wafers are moved to the cool portion of the reactor and then further cooled to room temperature.

Abstract: Indium phosphide stoichiometry in III-V semiconductor devices is sensitive to processing conditions during liquid phase epitaxy deposition. Disclosed is a method for determining indium-to-phosphorus ratio in an n-type indium phosphide semiconductor surface layer by monitoring photoluminescence at an absorption band at or near 0.99 electron volt.