Abstract: A method for fabricating a thin-film field effect transistor such as a thin-film field effect transistor. The method includes preparing a gate electrode on a substrate, anodizing at least a portion of the gate electrode to form a gate dielectric, and fabricating an electrically conducting source electrode and a drain electrode on the gate dielectric. The method also includes depositing an organic semiconductor on at least a portion of the gate dielectric, the source electrode and the drain electrode.

Abstract: A wavelength-selective add-drop multiplexer is disclosed for adding and/or dropping spectral components from a wavelength-division-multiplexed optical signal. (1.times.1) or (2.times.2) optical switches are used, either alone or in conjunction with other optical elements, to separate spectral components identified for drop from other spectral components.

Abstract: Distributed Bragg Reflectors of high efficacy based on alternating layers of large difference in refractive index are fabricated by epitaxial growth followed by etchant removal and back-filling to produce a structure in which alternation is between layers of retained epitaxially grown material and layers of back-filled material. Such reflectors may serve simply as mirrors or may be incorporated in a variety of devices including lasers, LEDs, detectors, optical switches in which the DBRs serve e.g. for cavitation.

Abstract: Optical integrated circuitry, performing various of the functions associated with electronic integrated circuitry, is disclosed. Fabrication, importantly to achieve high circuit chip density--typically in the range of 10.sup.6 as including both devices and interconnecting guides--is dependent upon device/spacing dimension miniaturization resulting from fabrication in very thin layers. Typical layer thickness as retained in fabricated devices and guides, of a maximum of the order of a 1/2 wavelength for relevant photon flux, results in limitation in cross-talk to permit device design rules of one or a few wavelengths.

Abstract: Polycrystalline and amorphous semiconductors can be annealed using a laser or electron beam to restore or obtain crystal order by epitaxial regrowth on a crystal substrate. When the annealing occurs by liquid phase epitaxy, the presence and lifetime of a molten state at the region being annealed can be used to control the annealing process. Various control mechanisms are described.