Abstract: A method and apparatus for producing a light conducting fiber having a core disposed in a loose fitting cladding tube characterized by a double crucible arrangement having a first crucible for a melt of the material for the cladding tube and a second crucible for the melt of the material of the core. The second crucible has an orifice of a given diameter and the first crucible has a ring-shaped orifice with an inner diameter greater than the given diameter of the orifice of the second crucible with the center of the ring-shaped orifice being arranged substantially on a central axis of the orifice of the second crucible so that a core drawn from the orifice of the second crucible is substantially concentrically disposed within the tube of material drawn from the ring-shaped orifice.

Abstract: A method for the production of single-material light-guiding fibers which have a core supported in a glass sheath in a cantilever manner by glass webs characterized by providing a crucible having an exit nozzle with an opening having a configuration of the cross section of the light-guiding fiber with a core portion connected by web portions to a surrounding annular portion, providing molten material of the light-guiding fiber in the crucible, drawing the molten material from the crucible through the exit nozzle to form a continuous integral workpiece having a core portion supported in a glass sheath in a cantilever manner by integral glass webs and continuously drawing the integral workpiece into the single-material light-guiding fiber. The crucible is formed by a pair of hollow bodies supported in an outer cylindrical member in a cantilever manner so that the cylindrical member and the pair of hollow bodies form the exit nozzle with the desired configuration.

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 for the production of gradient fibers of glass by depositing layers of glasses having selected indices of refraction and then drawing fibers therefrom. The process is carried out by sequentially introducing a plurality of glass masses to form layers having progressively higher refractive index of refractions. The resulting layers are formed into an unitary body which is drawn into an optic fiber.