Abstract: An integrated wavelength selectable photodiode includes a device package having an input that receives an optical signal. A set-and-hold, thermally tunable thin-film filter is positioned in the device package and includes an input that is optically coupled to the input of the device package. The set-and-hold, thermally tunable thin-film filter passes light with a predetermined optical bandwidth to an output. An optical element collimates an incident optical beam onto the input of the set-and-hold, thermally tunable thin-film filter. A detector is positioned in the device package and includes an input that is optically coupled to the output of the set-and-hold, thermally tunable thin-film filter. The detector detects data received by the integrated wavelength selectable photodiode.

Abstract: An improved fiber endface shape for increasing coupling of optical power from a source into fiber and its manufacture are disclosed. The inventive tip comprises a cleaved end surface that is preferably substantially orthogonal to the fiber's axis and a first and second polished, angled surfaces intersecting the end surface. Break-lines between the angled surfaces and the end surface fall near an edge of a cladding-core interface and preferably outside that interface when the fiber and transmitted light are such that a substantial portion of the light is transmitted in the cladding. A spatial intensity profile of light exiting from the tip is detected during manufacture and is used to monitor the polishing of the angled surfaces. Tests have shown that the inventive tip achieves the coupling efficiency associated with the double-angled wedge-shaped fiber tips while maintaining much of the ease of manufacture associated with the single-angle wedge tips.

Abstract: An improved fiber endface shape for increasing coupling of optical power from a source into fiber and its manufacture are disclosed. The inventive tip comprises a cleaved end surface that is preferably substantially orthogonal to the fiber's axis and a first and second polished, angled surfaces intersecting the end surface. Break-lines between the angled surfaces and the end surface fall near an edge of a cladding-core interface and preferably outside that interface when the fiber and transmitted light are such that a substantial portion of the light is transmitted in the cladding. A spatial intensity profile of light exiting from the tip is detected during manufacture and is used to monitor the polishing of the angled surfaces. Tests have shown that the inventive tip achieves the coupling efficiency associated with the double-angled wedge-shaped fiber tips while maintaining much of the ease of manufacture associated with the single-angle wedge tips.

Abstract: A ridge-waveguide laser is fabricated by epitaxially growing a GaAs-based heterostructure, disposing an AlAs etch stop layer on the heterostructure, disposing epitaxial layers on the etch stop layer, and etching the heterostructure to form the laser whereby the etch stop layer prevents further etching into said heterostructure.

Abstract: The I.sub.2 bound exciton in cadmium sulfide (bound to a neutral donor) is a very efficient radiator, providing low switching energy and fast switching times for an ON and OFF optical bistable device, desirable for all-optical signal processing applications. The optical bistable device for light at a given wavelength includes a Fabry-Perot cavity having a pair of opposed mirrored surfaces. A direct bandgap semiconductor, such as CuCl, CdSe, CdS, and GaAs having a bound exciton, is located within the cavity. The cavity is tuned near resonance of the light. The bound exciton has a coefficient of absorption tuned near resonance. A light beam of varying intensity is applied from without the cavity to one of the surfaces. The semiconductor has both an index of refraction and a coefficient of absorption that vary with the magnitude of applied light. Thus, light applied thereto passes through the device either substantially unimpeded or impeded, dependent upon its magnitude.

Abstract: An array of bistable devices includes a thin cadmium sulfide platelet having a first portion thereof that is substantially pure and the remaining portion thereof is implanted with atoms that can bind excitons. Such remaining portion can be implanted with ions from a lithium source. Apparatus for providing such an array can include a source of lithium ions and masking means for selectively permitting and for selectively inhibiting passage of ions from the source to pass therethrough and to implant in a pattern onto the platelet. The apparatus operates at temperatures in the neighborhood of liquid helium. A method for producing such an array includes providing a thin, substantially pure, platelet of cadmium sulfide, selectively masking the platelet with a pattern to selectively permit and to selectively inhibit passage of ions onto the platelet, and providing a source of ions. The source of ions, in accordance with certain features, can be lithium ions.

Abstract: Real-time all-optical multiplication of an n component vector by a large m by m matrix having digital accuracy utilizes an updatable two dimensional spatial light modulator.