Studies on the relation between the diffusion process and optical properties in Ti-diffused planar optical waveguides

Abstract

The kinetics of Ti diffusion into Y-cut LiNbO(3) was investigated. Scanning electron microscopy and Auger electron spectroscopy techniques were used to study the diffusion process, while end-fire and prism coupling of light at different wavelengths was used for optical characterization. A Gaussian profile was chosen as a solution to the diffusion equation, and the diffusion constant and the activation energy for this profile were found. By comparison of the result of optical measurements with numerical theoretical calculations, we obtained an empirical relation between the initial Ti thickness and the extraordinary refractive-index change.

Modelling Ti in-diffusion in

“…In this way, it is possible to increase the value of σ by increasing δ 0 and still have a highly asymmetrical profile. However, in this case, the switching time decreases to very small values, much lower than what is obtained experimentally (a few hours, depending on the film thickness and the diffusion temperature, as measured in [21]).…”