Electrooptical module

The module has an optically transparent, plate-shaped substrate with two plane parallel broad sides, an optical transmission element in a first fore-chamber in the first broad side, a beam shaping arrangement for coupling into a surface in a fore-chamber in the second broad side. The second broad side has a structured surface area that focusses the light passing through the substrate onto the input coupling surface. The first broad side has crystallographic (100) orientation. The first fore-chamber contains a flat surface of (111) orientation that reflects the transmitted beam onto the first broad side (11). The second broad side (14) fore-chamber contains an input coupling surface of a device which accommodate a holder for an optical waveguide. The structured surface is located so that the direction of the center ray (123,124) of the transmission beam deviates less from the perpendicular to the second broad side in the second broad side's fore-chamber than within the substrate.