Studies on the Propagation Characteristics. of Polarization Maintaining Optical Waveguides

Birefringent optical waveguides find use in a large number of applications such as coherent optical communication systems, interferometric fiber optic sensors, and polarization sensitive integrated optical devices. These waveguides include various polarization-maintaining optical fibers such as elliptical core fibers, bow tie fibers, and side tunnel fibers and integrated optical waveguides such as planar and strip waveguides. The present thesis is devoted to the study of the propagation characteristics of some of the polarization maintaining optical fibers and integrated optical waveguides. We first present a simple first order perturbation approach to study the various propagation characteristics of highly elliptical core fibers. The unperturbed waveguide is taken to be a pseudo-rectangular-core waveguide whose refractive index distribution is separable in the (transverse) x and y coordinates. Results obtained by the perturbation approach agree very well with those reported by using accurate numerical techniques. We have then proposed an equivalent rectangular core waveguide for studying the birefringent properties of elliptical core fibers. We have shown that, in the useful single mode region, the birefringent properties of elliptical-core fibers can be determined quite accurately by considering an equivalent rectangularcore waveguide having the same core area, aspect ratio and