Method of adjusting a polarization-independent optoelectrical change-over switch and a change-over switch for implementing the method

Polarization-independent optoelectrical change-over switch on a wafer of double-refracting crystal material with an optical axis Z. The change-over switch has a region of interaction L1 with optical waveguides 103, 104 and an electrode arrangement. The region of interaction L1 is divided into two sections S3, S4 with two inner electrodes 106, 107; 110, 111 and two outer electrodes 105, 108; 109, 112 in each section. Connected to the electrodes are voltage sources 114, 115, 116, 117; 118, 119, 120, 121 which generate electric fields through the optical waveguides 103, 104. The electric field between each of the outer electrodes 105, 108; 109, 112 and adjacent inner electrodes 106, 107; 110, 111 has in each section S3, S4 the same direction in both the optical waveguides and brings about δχ modulation. The electric field between the central electrodes 106, 107; 110, 111 has in each section S3, S4 mutually opposite directions in the two light waveguides and brings about a δβ modulation. In this way, both the cross- coupling state and the through-coupling state can be achieved for both the TE and the TM modes of an arbitrarily polarized lightwave P. The change-over switch can be operated with low voltages and the necessary manufacturing precision is relatively low.