ANALYSIS OF ELECTROOPTICALLY INDUCED WAVE-GUIDES IN STRONTIUM BARIUM NIOBATE AND OPTICAL MODULATORS

An electrooptically induced optical waveguide can be formed by applyin g a DC voltage between electrodes fabricated on the surface of a cryst al with strong electrooptic coefficients (for example, strontium bariu m niobate). Calculations of the refractive index profile and the optic al mode size for such waveguides are presented. Approximate solutions for the fundamental mode are used to analyse the power coupling betwee n a single-mode step-profile fibre and these waveguides. The power tra nsmission losses in the straight and S-shaped waveguides are estimated by using a finite-difference beam propagation method (FD-BPM). The ca lculations predict that a new kind of modulator/switch can be realized with the induced waveguides. The important characteristics of these d evices are discussed and compared with LiNbO3 optical waveguide modula tors.