Abstract: This application discloses a technique for producing optical fibers with longitudinal variations in index of refraction. The deposition apparatus is arranged to allow for the formation of an intertwined double helix of two different materials. The technique does not require imposing any time dependent conditions on the fabrication apparatus.

Abstract: Glass fiber lightguides require polymer coatings for protection. A new coating system comprising an acrylate-epoxy polymer that is UV cured is convenient to apply and gives excellent strength and durability to fiber lightguides.

Abstract: A method is disclosed for making strip material of a copper-nickel-tin alloy by cold rolling a homogenized ingot by an amount corresponding to an area reduction of from 25% to 45% followed by aging at a temperature in the vicinity of 350.degree. C. Strip material made by the disclosed method exhibits not only high strength but also high and essentially isotropic formability.

Abstract: An electric fuse is disclosed whose metallic fuse element is in a glassy state. The disclosed fuse is fast-acting and is particularly suited to protect delicate electronic apparatus against current overload.

Abstract: Infrared detection and transmission apparatus are disclosed which incorporate an infrared transparent window consisting essentially of thorium fluoride. Due to high resistance to thermal shock, thorium fluoride window material may be used to advantage under extreme atmospheric conditions or for the transmission of infrared radiation at high power levels.

Abstract: A graded index optical fiber with a structure which results in improved pulse dispersion characteristics is disclosed. The refractive index properties of the fiber core may be defined in terms of coaxially nested tubular regions, each of different index of refraction, which together form a radially graded index of refraction. The optical properties of each tubular region vary periodically along the longitudinal direction. The longitudinal variation of each tubular region is in approximate antiphase with the longitudinal variation of the tubular regions immediately adjacent to it. In the disclosed structure each tubular region is composed of at least two intertwined helical ribbons of material.

Abstract: In conventional processes for coating continuous filaments the filament is handled by various mechanical means such as, rollers, pulleys, etc. In the manufacture of, for example, optical fibers, such handling causes unacceptable mechanical damage to the fiber. Mechanical contact of the fiber being manufactured can be avoided by passing the fiber through a capillary wetted with a curable coating liquid. The flow of the coating liquid through the capillary is limited by reducing the pressure of the ambient above the liquid level within the vessel containing the coating liquid.

Abstract: A method is disclosed for making patterned gold films in the manufacture of integrated circuit devices. The method calls for the deposition of a film of a gold compound whose heat of formation is in the range of from -20 to +10 Kcal/mole, selectively reducing the gold compound to elemental gold by irradiation, and chemically removing the unreduced portions of the gold compound.

Abstract: An amorphous, stoichiometric, native, semiconductor oxide layer, with a sharp interface between the oxide layer and the substrate, is grown by directing electrons toward a semiconductor substrate in the presence of oxygen. The source of electrons may be a simple filament. This invention may be implemented with standard plasma growth techniques by extracting the electrons from the plasma production region and directing them to the substrate.

Abstract: The use of dopants enhances optical contrast and range of writing speeds in liquid crystal display devices. Such dopants are characterized by greater solubility in the isotropic phase than in the liquid-crystalline phase of a liquid crystal material.

Abstract: Copper alloys are disclosed which contain nickel and tin and Fe, Zn, Mn, Zr, Nb, Cr, Al, or Mg in amounts within specified limits. When cold worked and aged according to a critical schedule these alloys develop a predominantly spinodal structure which renders them strong as well as ductile. The disclosed alloys are useful, for example, in the manufacture of components of electrical apparatus such as springs, connectors and relay elements.

Abstract: A method is disclosed for producing optical fibers which are drawn with diameter variations in the transmitting core but with uniform overall diameter. In this process the glass starting member used in fabricating the optical fiber preform is etched with appropriate grooves. Additional glass is subsequently deposited on the etched starting member, and a fiber is drawn from the preform so fabricated.

Abstract: A liquid crystal twist cell is disclosed in which the transmission characteristics may be conveniently controlled so as to produce a grey scale. The elastic constants of the crystal are maintained within a specified range to enable the convenient variation of transmission characteristics.

Abstract: A method is disclosed for making precisely patterned platinum films in the manufacture of integrated circuit devices. The method calls for the deposition of a film of a platinum compound, whose heat of formation is in the range of from -100 to +10 Kcal/mole, patterning the film, and thermally reducing the patterned film to platinum metal.

Abstract: An improved liquid crystal twist cell with significant reduction in the undesirable "optical bounce" and off axis interference phenomena is described.

Abstract: The specification describes a procedure for multilevel metallization of semiconductor integrated circuits in which the severity of the step formed by the edges of the first level pattern and the intermediate insulator over which the second level metallization pattern extends is reduced by beveling the edge. The bevel occurs during selective etching of the first level metal as a consequence of depositing the first level metal over a range of diminishing temperatures. Metal layers, notably aluminum, deposited in this way exhibit a differential etch rate such that the layer etches more slowly as etching proceeds through the thickness of the layer. Bevels of the order of 30.degree. to the horizontal can be produced in this way.

Abstract: Optical fibers in long line communication links fail often in tensile strength. Analysis of tensile properties reveals a variation in tensile strength with fiber length, pointing to uncommon structural defects randomly occurring along the fiber length. Failures occur from crack propagation at these defects. The defects can be revealed according to the invention by nondestructive monitoring during production via off-plane light scattering. A narrow light beam incident across the fiber diameter is refracted in a pattern characteristic of the fiber geometry. Variations in that pattern are produced by structural variations in the fiber or by surface contamination. The nature of the pattern change can indicate the type of defect.

Abstract: This application discloses a technique for producing optical fibers with longitudinal variations in index of refraction. The deposition apparatus is arranged to allow for the formation of an intertwined double helix of two different materials. The technique does not require imposing any time dependent conditions on the fabrication apparatus.

Abstract: A method is disclosed for growing neodymium doped yttrium aluminum garnet crystals from a melt containing constituent oxides, lead oxide, lead fluoride, and boron trioxide. By subjecting the melt to a controlled temperature cycle while maintaining a temperature gradient in the melt, large size, high quality crystals are obtained. Crystals produced by the disclosed method are suited for laser application.

Abstract: A method of continuously producing clad composites is disclosed. The cladding is combined with a resin-wet reinforcement and pultruded through a forming and curing die in a single processing step.