Abstract: An inside lining for the reaction chamber of an electric low shaft furnace, particularly for producing high-purity silicon from silicon oxide by carbothermic reduction, is provided which has a melting crucible of dense graphite and a thermal insulation, whereby at least the floor of the reaction chamber has an inside lining of high-purity carbon. The inside lining is constructed from graphite, graphite grits or lampblack. The inside lining provides good thermal insulation and does not further contaminate the molten metal due to furnace materials. The inside lining prevents a loss of material in that seepage of molten metal into the insulation is prevented by a rapid dropoff of the temperature in the insulation below the melting point of the metal.

Abstract: The present invention provides a heterogeneous catalyst based on silicon dioxide, as well as, a method for manufacturing same. The catalyst of the present invention is constructed from a porous material produced from large-surface glass bodies containing catalytically active additives by leaching with mineral acid and the additives are incorporated into the network of the glass body in the form of metal oxides insoluble in hot mineral acid. The catalyst exhibits a high active surface and is universally employable because it contains only a slight amount of undesired impurities, is highly reactive, and has a high structural stability up to about 1000.degree. C.

Abstract: In a method for separating solid reaction products from silicon produced in an arc furnace, molten silicon produced in the arc furnace in a reduction of SiO.sub.2 and carbon is filtered through a heated layer composed of SiC/Si after a so-called holding phase at a temperature in a region above a melting point of the silicon. The layer is preferably fashioned as a bottom plate of a crucible. The melt has eliminated from it SiO.sub.2 and SiC particles contained therein. The method serves for the production of silicon for solar cells. Due to the separation of SiO.sub.2 and SiC out of the molten silicon, an efficiency of above 10% is achieved in the solar cells fabricated from this material.

Abstract: The invention concerns a process for the manufacture of substrates from carbon-coated SiO.sub.2 fabric that can be used for large-surface silicon bodies, in which mineral materials or waste containing SiO.sub.2 are used as starting materials and a mixture of Al.sub.2 O.sub.3 and oxides of the alkaline and/or alkaline earth metals is used as a flux for the transformation into the glass phase. The glass fibers made from the homogenous glass melt are processed into a glass fabric, which is then subjected to an acid leaching process and coated with carbon. The process is used for the low-cost production of substrates for silicon bodies that are manufactured according to the strip-coating process for use in solar cells.

Abstract: Highly purified starting materials for the production of silicon suitable for fabrication of solar cells are produced via the carbo-thermal reduction process. A carbon-containing material with impurities therein, either by itself or admixed with glass bodies, which are attained from a melt of quartz sand and glass-forming additives formed into a fiber form and pulverized, is converted into a granulate form with the aid of a bonding agent. The resultant granulates are contacted with a hot inorganic acid, such as 3N HCl at about 90.degree. C., to extract substantially all impurities from the granulates, which can be in pellet or tablet form. The resultant purified pellets are then directly charged into an electrical arc furnace to yield solar-quality silicon. With this process, highly purified SiO.sub.2 and highly purified carbon are produced in a simple and cheap manner. The impurity level for boron, phosphorus and transition metal in these starting materials is less than about 10 ppm.

Abstract: A method for manufacturing distributor and mixer elements for optical communications technology, which elements have at least two glass fiber light waveguides fused to one another along a given segment, characterized by the steps of forming a preform by arranging at least two fiber optical rods to extend parallel to each other, fusing the arranged rods to one another in at least one sharply limited longitudinal area, then subsequently heating the preform and drawing the elements therefrom.

Abstract: An optical fiber having a core surrounded by a cladding layer which has an index of refraction less than the index of refraction of the core characterized by a longitudinal side coupling zone being formed by a longitudinal opening extending through the cladding layer of the fiber to expose a portion of the core. The optical fiber of the invention is particularly useful in conjunction with a light sensitive detector and is useful in a mixer where more than one fiber are joined together either in a bundle or in a strip configuration. The fiber with the side coupling zone can be formed by drawing the fiber from a workpiece having a core or rod member surrounded by a sleeve member or layer which is provided with the opening or can be drawn from a molten material utilizing a double crucible in which the opening of the inner crucible is provided with at least one bulge extending to the edge of the opening of the outer crucible.

Abstract: An optical fiber having a core surrounded by a cladding layer which has an index of refraction less than the index of refraction of the core characterized by a longitudinal side coupling zone being formed by a longitudinal opening extending through the cladding layer of the fiber to expose a portion of the core. The optical fiber of the invention is particularly useful in conjunction with a light sensitive detector and is useful in a mixer where more than one fiber are joined together either in a bundle or in a strip configuration. The fiber with the side coupling zone can be formed by drawing the fiber from a workpiece having a core or rod member surrounded by a sleeve member or layer which is provided with the opening or can be drawn from a molten material utilizing a double crucible in which the opening of the inner crucible is provided with at least one bulge extending to the edge of the opening of the outer crucible.

Abstract: The invention relates to a method for manufacturing a hihg-tensile strength optical waveguide with a plastic layer of the epoxy-acrylate type located on the lightguide fiber, wherein a radiation-hardenable prepolymer is applied to the lightguide fiber immediately after the fiber-drawing process. The invention provides for the use in such a method of a preopolymer, which can be hardened by actinic radiation, of at least one acylated hydroxy ester of acrylic and/or methacrylic acid and an epoxide with n.ltoreq.3 epoxide groups per molecule. The optical waveguides manufactured by the method according the present invention are suitable particularly for purposes of optical information transmission.

Abstract: The present invention relates to a method for the manufacture of a high-tensile-strength light waveguide with a plastic layer on the optical fiber, in which a hardenable polymer precursor stage is applied to the optical fiber. Uniform, thick layers are produced in a single operation in a process comprising applying an oligomeric and/or polymeric polyaddition or polycondensation product to the optical fiber from a solution and subsequently irradiating with actinic light and/or performing a thermal treatment. The polyaddition or polycondensation product is made from a carbocyclic or heterocyclic compound which carries two functional groups suitable for addition or condensation reactions, and a diamine, a diisocyanate, a bis-acid chloride or a dicarboxylic acid. The carbocyclic or heterocyclic compound has in a position adjacent to the functional groups partially ester, amide, urethane or urea groupings which may be of an unsaturated nature.

Abstract: An optical unit having at least one longitudinal side coupling zone characterized by the unit comprising at least one glass fiber having a glass core with a glass cladding layer surrounding the core with a step in the index of refraction from a greater to a lower value occurring at the junction between the glass core and cladding layer, the cross section of the glass fiber remaining uniform along the entire length and the core having at least one constriction to form the longitudinal coupling zone. To form the optical unit, a device utilizing a double crucible with a nozzle opening of the inner crucible being arranged to discharge into the nozzle opening of the outer crucible and provided with a means for regulating the flow therethrough is utilized.

Abstract: The present invention is directed to an improvement in a magneto-optical device having a light waveguide for conducting light characterized by the light waveguide being a cladded optical fiber having a core of quartz glass and a cladding of synthetic material. This improvement provides an improved method of using the magneto-optical device by suppressing distortions of polarized light by reducing birefringence in the waveguide by using a waveguide comprising an optical fiber having a quartz glass core and a cladding of synthetic material.

Abstract: Relatively pure Si (having less than about 1 ppm of detrimental impurities therein) is obtained from ordinary quartz sand by uniformly admixing such sand with suitable glass-forming materials, such as boron oxide and alkali-metal carbonates or oxides, melting such admixture to form a glass, annealing the glass so as to obtain a phase separation comprised of an SiO.sub.2 -- rich phase and an impurity-rich phase, extracting the impurity-rich phase via strong acid, such as nitric acid, washing and drying the remaining glass and reducing such glass with carbon-containing compounds, such as graphite, sucrose, starch, etc., in an electric arc. The so-obtained relatively pure silicon is suitable for fabrication into semiconductor components, such as solar cells.

Abstract: A double crucible system is disclosed for the production of light conducting fibers. The system has an interior crucible which can be axially displaced in relation to the exterior crucible which is concentric thereto. The spacing of the crucible jets in the exterior and interior crucible in relation to one another is thereby altered so that the proportion of the cross-sections of the fiber core and the fiber casing is continuously altered.

Abstract: A process and apparatus for producing light conducting fibers characterized by introducing multi-component glasses into a quartz glass crucible, melting the multi-component glasses, homogenizing and refining the melt, subsequently drawing the glass fiber through an opening in the base of the quartz crystal and then coating the fiber with an optically active synthetic material. During the homogenizing and refining of the melt, gas, such as dry oxygen, is introduced and passed through the melt. So that fibers of any length can be drawn, additional glass material in the form of premanufactured, highly pure glass rods are introduced into the crucible as necessary.

Abstract: An optical unit having at least one longitudinal side coupling zone characterized by the unit comprising at least one glass fiber having a glass core with a glass cladding layer surrounding the core with a step in the index of refraction from a greater to a lower value occurring at the junction between the glass core and cladding layer, the cross section of the glass fiber remaining uniform along the entire length and the core having at least one constriction to form the longitudinal coupling zone. To form the optical unit, a device utilizing a double crucible with a nozzle opening of the inner crucible being arranged to discharge into the nozzle opening of the outer crucible and provided with a means for regulating the flow therethrough is utilized.

Abstract: A light waveguide with a high tensile strength including a light conducting or optical fiber being coated with a plastic coating to improve the tensile strength characterized by the plastic coating being a plastic lacquer applied directly on the surface of the light conducting fiber, being a high temperature stable material selected from a group consisting of polyurethanes, epoxides, polyesters, polyesterimides, polyimides, and polyvinyl dimethoxymethane, which material has a softening temperature of at least 150.degree. C. The coating has a thickness of at least 2 .mu.m and is uniformly concentrically applied over the entire length of the light conducting fiber without any surface defects. The light waveguide may include an outer covering which is either tightly applied or loosely applied onto the light conducting fiber and its coating. To improve movement of the light conducting fiber and its coating in the covering, a slide layer may be interposed between the outer covering and the plastic lacquer coating.

Abstract: A device for drawing a plurality of cladded light conducting fibers utilizing a double crucible having an inner crucible and an outer crucible with each of the crucibles having a bottom and receiving a melt of the respective material, and having nozzle pairs with the nozzle of the inner crucible being aligned axially with the nozzle of the outer crucible, the device including a device for gathering the pulled fibers to form a bundle and for coating the pulled cladded fibers characterized by the nozzles being exclusively arranged at points on the bottoms of their respective crucibles where the same temperature prevails for the glass melt present in the double crucibles. To accomplish this, the nozzles are located between and equal distance from the parallel boundary lines of the bottom of the inner crucible so that the melt drawn through the nozzle travels the same distance in all directions.

Abstract: A method of producing a light conducting fiber by providing a rotating, heatable crucible having a cylindrical interior wall, successively depositing optical material forming layers from a liquid phase with the first layer being deposited on the interior wall of the rotating crucible and subsequent layers being deposited on a previous deposited layers, transforming each layer into a film of optical material to form a workpiece having a plurality of concentric cylindrical films of optical materials, and subsequently pulling the fiber from the workpiece while it is still in the crucible.

Abstract: A method of producing a light conducting fiber comprises the steps of providing a base member of an optical material such as glass or a synthetic glass-like material, depositing at least one optical material forming layer such as a glass forming layer or a synthetic glass-like material forming layer from a liquid phase on a surface of the base member and subsequently transforming each of the layers into a film of optical material such as a glass film or a synthetic glass-like film. The base member may be a glass tube and the optical material forming layers may be deposited on an interior surface and after the layers have been transformed into a film, the tube is collapsed into a rod and then subsequently drawn into a cladded light conducting fiber. In one embodiment of the invention, the base member is a rod and the layers are deposited on a surface of the rod which is subsequently drawn into a cladded light conducting fiber.