Abstract: An optical device is disclosed which provides wavelength multiplexing/demultiplexing utilizing a plurality of focusing Bragg reflectors. Each Bragg reflector includes a plurality of confocal (i.e., common foci) elliptical grating lines, with the exit/entrance ports of the input/output waveguides located at the foci of the ellipse. By virtue of the elliptical design, the signal propagating outward from the exit port of the input waveguide will be reflected by the appropriate Bragg reflector and focused into the entrance port of the appropriate output waveguide. When each Bragg reflector exhibits a different ellipticity, but shares one common focal point, optical multiplexing/demultiplexing may be achieved. Optical filtering may be achieved when all Bragg reflectors are designed to have common foci.

Abstract: In the interest of ease of manufacture, hybrid lasers of distributed-Bragg-reflector type are preferred for use as light sources in optical communications. Such lasers are made to operate away from mode instabilities by adjusting a laser parameter such as, e.g., laser temperature, thereby assuring highly error-free transmission. Alternatively, by suitable design of the Bragg reflector it is possible to render mode instability of negligible influence on error rate.

Abstract: Highly frequency-selective reflectivity is realized in an optical device including a waveguide and an evanescent-field coupled grating resonator cavity. The device may include a light source and serve as a low-chirp, narrow-linewidth communications laser for use, e.g., for transmission over a fiber having non-negligible dispersion and also in wavelength-multiplexed coherent systems.

Abstract: For achieving dense packing of MOS transistors at the top surface of a silicon semiconductor body, second level metallization including arsenic doped polysilicon contacts are used in conjunction with a phosphorus gettering step at a time when the top surface is sealed against the introduction of phosphorus by an undoped sacrificial glass layer, i.e., which is essentially free of phosphorus. The second level metallization is thereafter completed by coating the polysilicon with a high conductivity metal, such as aluminum. During the gettering, the polysilicon contacts are insulated from the first level metallization by a planarized glass layer doped with phosphorus to a concentration below the saturation level of phosphorus in the glass.