Abstract: A process for coating at least one optical waveguide with a filling compound has at least two successive filling stages separated by a wiping device of reduced cross section. In the region of the wiping device, a proportion of the filling compound which is thus wiped off is led past the wiping device by a bypass and is fed once more to coat the optical waveguide in the second filling stage.

Abstract: An apparatus for filling the interspaces between leads of a bundle of leads, which may be optical or electrical leads, with a water-repelling compound characterized by a filling head having a pre-filling chamber and a main filling chamber. The leads are supplied via a common admission channel to the pre-filling chamber which has a channel opening that is selected to be only slightly larger than the diameter of the envelope of the leads combined to form a bundle of leads. The pre-filling chamber is followed by a coating nozzle having a diminished cross section, which coating nozzle receives the bundle and discharges it into the main filling chamber.

Abstract: A method for covering at least one optical fiber with a protective layer comprises extruding the protective layer and embedding reinforcing elements in the protective layer to form a composite covering and simultaneously introducing the optical fiber into the composite covering. The method includes introducing a single waveguide or a plurality of waveguides, which may be formed into a bundle with a filling compound.

Abstract: A process for forming a plastic casing having reinforcing elements to resist tensile forces by simultaneously extruding the plastic casing and the reinforcing elements which are in a molten form and then twisting the extruded casing and elements to impart a helical configuration to the elements.

Abstract: A protective sheath for an optical transmission element is constructed of an inside layer of polycarbonate and an outside layer of a material which has a high degree of crystallization with the crystallization temperature of the outside layer preferably being below the softening temperature of the polycarbonate used for the inside layer so that the heat of crystallization release during crystallization will retard the cooling of the inside layer to produce solidification of the inside layer from the inside of the element toward the outside.