Abstract: An optical switch has a substrate and a transparent material in which a three-dimensional diffraction pattern is recorded which is capable of diffracting light, the material having non-linear optical properties and extending in the form of a first layer above the substrate. At least one first electrode and at least one second electrode are provided for varying the diffraction pattern in accordance with applied voltages.

Abstract: A method is described of producing an elongated glass body, particularly a preform for SiO.sub.2 -base optical waveguides, in which starting glass powder material is shaped to a porous body and the latter is sintered to form a glass body. In order to obtain uniform density throughout the porous body, the starting glass powder material is filled into and simultaneously compacted in a mold. Subsequently, the powder material compacted during the filling is consolidated by a heat treatment to result in the porous body. Molds of different design for the production of tubular or rod-shaped porous bodies are described.

Abstract: For fabricating porous bodies from a glass starting material, particularly in connection with the fabrication of an optical waveguide preform, it is proposed to fill powdery glass starting material under a pre-compaction into a compression mold, and to compress it thereafter. When the porous body to be formed is to have a varying composition in the radial direction, as is necessary with a view to step index optical fibers or optical waveguides having a graded index of the refractive-index profile, then differently composed powdery glass starting materials are filled one at a time, in adjacent coaxial areas, into the compression mold. This is effected with respect to each of the individual areas with the aid of a screw conveyor under a continuous, adjustable pressure and at an adjustable conveying speed.

Abstract: In a stripe-geometry multimode laser having a current-flow-determining stripe, only the flow of electric current is confined to a narrow area, while the heat can flow off through a large area. A window for the flow of electric current is formed by a narrow epitaxial semiconductor stripe which, because of its high doping level and of additionally diffused charge carriers, is highly conductively connected to both the underlying semiconductor and the overlying metal, while next to the stripe, electric conductivity from the semiconductor to the metal is very poor. The thermal conductivity, however, is approximately the same over the entire area.

Abstract: A positioning device comprising a bolt having a transducer and an optical waveguide fixed inside a guide sleeve mounted concentric with the longitudinal axis of the bolt. Supporting members on the bolt for the transducer and the guide sleeve are arranged in a spaced relation. The supporting member for the guide sleeve comprises a semi-cylindrical shell provided with an extended supporting arm on which the sleeve is mounted. A plate-shaped supporting member for the transducer is mounted in the shell. To achieve an improved separation of the heat-flow paths, slots are cut on opposite sides of the supporting arm into the shell.