Full-vectorial wave propagation in semiconductor optical bending waveguides and equivalent straight waveguide approximations

Device characteristics of optical polarization rotators are founded upon the vector properties of the Maxwell Equations. Recently, a bending waveguide based polarization rotator has been proposed and demonstrated. To provide a rigorous basis for the analysis and design of this polarization rotator, the full-vectorial wave equations for both (E) over right arrow- and (H) over right arrow-field in bending waveguides are derived. It is found from these wave equations that under a broad range of circumstances, a bending waveguide can be analyzed using the equivalent straight waveguide approximation, Details of the model for optical polarization rotators, which is based on the coupled-mode theory, will be described in a companion paper.