Design of Ti:LiNbO3 single mode waveguides for 0.83μm

A channel waveguide is the basic structure of any integrated optical device for Optoeletronic applications. The equations governing a channel guide are quite complex and are not available in closed form [1,2]. The design aspect of channel guides following Marcatilli, method has been reported by K R Suresh et al [3]. In this paper we have applied a different procedure to design the channel waveguides using effective index method and ray approximations which appreciably simplify the calculations. From the published experimental data on Ti diffusion in LiNbO3, temperature dependent diffusion constants are extracted. Diffused Ti concentration profiles and corresponding index profiles have been worked out using error functions in depth and width directions. A set of values of sputtered Ti film thickness and guide width for the. permissible index difference to support fundamental mode propagation has been computed. Simple steps are described, with examples, to calculate the propagation constant and the mode angle from eigen value equations.