Abstract

Light propagation in biaxially anisotropic dielectric crystals may be conveniently described by the two-sheeted wave vector surface. Each sheet represents the properties of one of the two allowed orthogonally polarized propagating waves. In general, the two allowed propagating waves are "extraordinary-like," and the Poynting (ray) vector direction for each wave differs from the wave vector direction. Dielectric planar waveguides may be biaxial, either naturally or through the electro-optic effect (as is frequently the case with modulators). The electromagnetic fields in a biaxial waveguide consist of a weighted sum of four "extraordinary-like" plane waves which are coupled. The directional properties of the hybrid guided modes are determined by using a complete and concise coordinate-free approach for isolating each sheet of the wave vector surface. The ranges of propagation constants for the hybrid modes are determined as a function of the orientation of the principal dielectric axes, and this leads to the classification scheme that uniquely identifies each guided mode.

© 1990 Optical Society of America