| Integrated optics, driven by the need for high-speed, high-volume signal processing, has made significant progress. However device development has been limited by a lack of fundamental understanding in many areas. The anisotropic characteristics of propagation in dielectric waveguides represent such an area in need of basic research. Integrated optical devices employ anisotropic materials because of their useful characteristics such as low loss and large electro-optic, photoelastic, and photorefractive effects. The anisotropic nature of the waveguide have been ignored. However due to the anisotropy, for example, the guided modes are neither transverse electric (TE) nor transverse magnetic (TM) modes but are hybrid in general, and the phase propagation direction and power propagation direction do not necessarily coincide.;A more complete understanding of the propagation of modes in anisotropic waveguides is obtained by allowing an arbitrary optic axis orientation in the analysis of a three-layer step-index uniaxial waveguiding structure. Hybrid guided modes can be divided into three types: homogeneous pure guided, inhomogeneous pure guided, and leaky guided modes. Pure guided modes propagate without loss, whereas leaky guided modes are attenuated. In this thesis the conditions for the existence of pure guided and leaky guided modes in uniaxial waveguides are presented. The cutoff conditions for guided modes in uniaxial waveguides are discussed. Rigorous methods are presented to calculate the propagation constants, field distributions, and power flow directions of pure guided modes. A quantitative method of classifying each mode is introduced that is based on the guided mode propagation constant bands. Each mode is labeled in terms of the limiting optic axis (... |
