The ?telephone effect? on formants: a response

A wave-guide structure for use in optical communications and a method of producing the wave-guide structure characterized by a substrate of a given index of refraction, a wave-guide layer having lateral edges and a different index of refraction disposed on a surface of the substrate and a multi-layer system extending through the wave-guide layer between the lateral edges to separate the wave-guide layer into two wave-guide portions which are integral with the multi-layer system and in planar alignment with each other, the multi-layer system comprises a plurality of layers with different indexes of refraction which layers extend at either a right angle or oblique angle to the surface of the wave-guide layer and at either a right angle or an oblique angle to the lateral edges so that radiation transmitted in one of the wave-guide portions has an angle of incident with the multi-layer system. The multi-layer system may extend partially ito the substrate or completely therethrough. The method of producing the various wave-guide structures includes providing a substrate having at least one flat surface, either cutting a groove in the substrate to subdivide the flat surface or cutting the substrate into a pair of substrate portions, applying the multi-layer system either to a side wall of the groove or one of the cut surfaces, and providing the formation of wave-guide layers on the flat surface.