PLANAR ELECTRO-OPTICAL LIGHT BEAM DEFLECTOR AND PROCESS FOR PRODUCING THE SAME

摘要

A planar electro-optical light beam deflector has a row of adjacent deflecting prisms with electrodes to which an electric voltage may be applied. The invention essentially consists in that the light beam is guided in a zero-degree cut lithium niobate or lithium tantalate crystal, preferably in a monomode laminated waveguide that extends along the surface of the same, and in that the deflecting prisms consist each of two triangular or prismatic areas in which a substantially uniform sense of polarisation is generated in areas with spontaneously opposite senses of polarisation by reversing the sense of polarisation determined by the electric field vector. Adjacent triangular areas have opposite senses of polarisation. A rectangular electrode that covers the triangular areas is applied on the top surface of the crystal and a counter-electrode is applied on the lower surface of the crystal. As a result of these measures, a change in the index of refraction with opposite signs is induced in the adjacent triangular or prismatic areas when a voltage is applied between the electrode and the counter-electrode. The index of refraction distribution is an almost ideal saw-tooth distribution. Also disclosed is a process for producing such a light beam deflector.