LOW-LOSS OPTICAL WAVE-GUIDE BENDS CONSISTING OF UNIAXIAL CRYSTALLINE MATERIAL

This paper presents a theoretical study on transmission properties of bent optical waveguides of uniaxial anisotropic material. The waveguid ing structure consists of two parallel straight slab waveguides connec ting by an oblique section. By arranging the direction of the optical axis in the oblique section so that the wave normal always points to t he same direction throughout the waveguiding structure, low loss trans mission can be realized. The analysis of wave propagation through the structure is based on the finite difference beam propagation method. N umerical results indicate that by optimally arranging the direction of the optical axis in the oblique section power coupling coefficients b etter than 95% can be obtained for any tilt angle of the oblique secti on when the tilt angle is smaller than 2 degrees. Some held distributi ons are also presented along the waveguiding structure.