Abstract: Sol-gel process conducted under an inert gas in a solvent at a temperature up to the boiling points of the solvent and by-products by reacting a chalcogen source, a glass network former-intermediate metal in the form of an alkoxide or a non-alkoxide and a catalyst to form a homogeneous product having average particle size of below 100 nm with catalyst, if the catalyst is a catalyst dopant, uniformly dispersed in the particles.

Abstract: A method for manufacturing a glass preform from a metal sulfide chalcogenide glass to which a large amount of light emitting substances can be added includes steps of etching a surface made of the chalcogenide glass or oxychalcogenide glass of disc shape core and clad forming glass starting materials by an etchant including an acid and a compound reacting with a hydrogen chalcogenide, and forming the core forming glass starting material and the clad forming glass starting material into a united body serving as a glass preform. In a method for manufacturing a single-mode glass fiber using a preform method by drawing the glass preform whose outer round surface is made of a chalcogenide glass or oxychalcogenide glass, the outer round surface of the glass preform is etched using an etchant including an acid and a compound reacting with a hydrogen chalcogenide and then drawn into the glass fiber.

Abstract: Hydrogen and/or carbon impurities are removed from chalcogenide or chalcoide glasses by the addition of a halide, such as TeCl.sub.4, to the batch composition. During melting of the batch composition, the metal halide reacts with the hydrogen and/or carbon impurities to form a hydrogen halide and/or carbon tetrahalide gas and a metal which becomes incorporated into the chalcogen-based glass. Useful halides include halides of sulfur, selenium, tellurium, polonium, or halides of a metal (such as aluminum, magnesium, zirconium, or a mixture thereof) that forms a stable oxide. Mixed metal halides may also be used. The glass melt is then distilled, outgassed, homogenized, fined, and annealed. An apparatus specially designed for making a fiber preform by the above process is also described. An annealed preform made by this method may be drawn into a low-loss fiber in the 2 .mu.m to 12 .mu.m range.

Abstract: An infrared transmitting chalcogenide glass lens having precision optical surfaces of different curvature radii is molded. A pair of molds having different curvature radiuses from each other, and a bushing which controls the thickness of the lens is provided. A block of chalcogenide glass is placed within the cavity. The upper mold, the lower mold and the block of glass are heated with the mold having a smaller curvature radius being at a higher temperature than the other mold. The glass is then pressed, cooled, and the resulting lens is removed from the mold assembly.

Abstract: This invention pertains to optical waveguides which includes waveguides of ll shapes and sizes, preforms, and optical fibers made from the preforms, and to a method for making waveguides devoid of a physical interface.

Abstract: A process for producing optical fibers of high tensile strength, wherein the fiber is pulled from a glass mass of halide glass and includes surrounding the fiber and mass with a dry gas atmosphere containing a drying agent which reacts with moisture and this dry gas atmosphere includes fluorine-containing agents, in particular NF.sub.3, as the drying agent.

Abstract: The method involves producing a multi-component glass doped with CdS.sub.x Se.sub.y Te.sub.z microparticles. The process has solved the conventional problems that the chalcogen element(s) to constitute the microparticles is (are) vaporized at the step for obtaining a glass melt, by specifying (a) the material to become a glass matrix and (b) the atmosphere used for obtaining a glass melt. The method involves using a mixture of elemental Cd and at least one of the elements S, Se and Te.

Abstract: A method for fabricating defect-free optical fiber preforms without light scattering defects such as core-clad interface bubbles, core-clad crystalline inclusions and core glass crystals involves first forming a cladding glass shell preferably by rotational casting, then separately melting core glass inside a cylindrical crucible and quenching using metallic quenching blocks to prevent crystal formation in the core glass, next heating the core containing crucible to the core glass softening point and also heating the cladding tube containing mold to the glass transition temperature of the cladding glass, then placing the cladding tube containing mold inside the core glass crucible and pushing it downwardly with high pressure so that the softened core glass is forced into the cladding glass tube, and finally the preform is annealed to remove thermal stress. Subsequently, the preform is drawn into optical fibers using conventional technology.

Abstract: A method for foming glass articles of substantial thickness from unstable glass compositions which normally devitrify when formed by conventional casting or molding processes, is disclosed. The method includes the steps of quench-cooling the glass to form a crystal-free glass feedstock material, and then pressure-consolidating the feedstock at a temperature between the transition temperature and the crystallization temperature of the glass.

Abstract: A multi-component glass doped with microparticles of CdS.sub.x Se.sub.y Te.sub.z, which can be used as a material for sharp cut filter, a material for infrared-transmitting filter or a nonlinear optical material. This glass has solved the problems of conventional glasses doped with microparticles, of (a) being low in microparticles concentration and accordingly having a low spectral characteristic when made into a thin filter and (b) being low in microparticles concentration and accordingly having low third-order nonlinearity, by containing microparticles at a high concentration, i.e. 5-50% by weight. The present invention relates to a process for producing the above multi-component glass doped with CdS.sub.x Se.sub.y Te.sub.z microparticles.

Abstract: The present invention relates to a process for producing a glass doped with dispersed microcrystallites, said process comprises:a first step of cooling a glas melt comprising a component to become a glass matrix and a component to become microcrystallites dispersed in said matrix, to a temperature T which is not higher than the flow point of the glass but not lower than the sag point of the glass, anda second step of maintaining the cooled glass at the temperature T to precipitate microcrytallites in the matrix.The glass doped with dispersed microcrystallites produced is used as a material for sharp cut filter, a material for infrared-transmitting filter, a nonlinear optical material, etc.

Abstract: A process for producing a chalcogenide glass fiber which comprises placing a cylindrical chalcogenide glass preform vertically in a cylindrical crucible furnished with a nozzle in its bottom portion, heating the crucible only at vicinity of the nozzle, and continuously drawing the glass into a fiber with the temperature of the crucible at the vicinity of the nozzle being maintained at such a level that the viscosity of the glass is within the range of 10.sup.3 to 10.sup.7.5 poises.

Abstract: Heavy metal fluoride glasses are made by a process that requires high purity fluoride constituent compounds fluorinated oxides, or premelted glass cullet. The charge is placed in an enclosed furnace chamber having the ability of atmosphere control, heat control and position control of the charge. In particular, an inert, or nonreactive atmosphere or air is used in the furnace chamber as well as an oxygen-scavenging metal therein. The oxygen-scavenging metal at the high temperature produces a controlled oxygen partial pressure so that the air is essentially inert and non-reactive although the presence of a slightly oxidizing atmosphere is still required to produce the glass. The charge is rapidly raised to its fusion temperature and held at the temperature for a short time in proximity to an oxygen-scavenging material. The charge is immediately removed from the heating source and quickly cooled through the critical crystallization region. The total heating and cooling time being less than one hour.

Abstract: Planar single-mode optical waveguides which can conduct light with defined polarisation have so far been embedded in, for example, a cladding made from crystalline LiNbO.sub.3. The crystalline structure of the cladding produces disadvantageous properties such as the fact that the birefringence depends on the geometric profile of the guide, relatively high optical loss, poor fibre coupling, birefringence rigidly fixed by material constants, and a costly manufacturing process. The new process results in an optical waveguide in which both the cladding and the actual guide itself are made of glass with a certain composition, thereby avoiding the disadvantages stated. With the help of a non-isothermal plasma CVD process a light-guiding core region (1) is surrounded on a substrate (4) by cladding layers (2, 2') and a cladding region (3, 3'), the thermal coefficient of longitudinal expansion of the cladding region (3, 3') differing markedly from that of the two homogeneous cladding layers (2, 2').

Abstract: A chalcogenide glass rod and/or a fluoride glass rod are covered with a thermally shrinkable synthetic resin tube, the resulting assembly being heated under vacuum to produce a preform, and a thermally shrinkable synthetic resin tube with a plurality of said preforms formed in a bundle and inserted thereinto is drawn again under heating.

Abstract: A selenium-base chalcogenide glass for use as optical fibers suitable for transmitting with low loss infrared rays, particularly that of 10.6 .mu.m in wavelength, is provided. The infrared optical fibers with low transmission loss, which is suitable for practical use, are obtained by incorporating 2 to 100 ppm of at least one of Al Ga, and In into a selenium-base chalcogenide glass, thereby to reduce the absorption due to the vibration of Ge--O bond formed by the contamination with oxygen. The infrared optical fibers made of such a glass material show a transmission loss of 3-4 dB/m which is less than 1/2.5 of the loss (10 dB/m) of a reference glass.

Abstract: An hermetic seal at a smooth interface between a gallium arsenide body and a glass body is effected without organic or inorganic binders by thermally bonding the bodies at the interface while ensuring that the oxygen concentration at the interface is so low that there is no optically detectable variations in color of the gallium arsenide close to the interface.

Abstract: A method of treating a silicon single crystal ingot which comprises the steps of purposely producing lattice strains in a silicon single crystal ingot, annealing the ingot at high temperature, and etching off the surface of the annealed ingot, thereby suppressing the occurrence of lattice defects.