Secondary-ion-mass spectrometry and near-field studies of Ti:LiNbO3 optical waveguides

Abstract

Secondary-ion-mass spectrometry (SIMS) and near-field (NF) methods have been applied to study Ti:LiNbO3 optical waveguides. Ti concentration as a function of diffusion process parameters has been studied by the SIMS method. The main determining factors that were found to affect the depth-diffusion behavior of titanium in LiNbO3 slab waveguides are the initial thickness of the dopant film and the diffusion temperature. Anisotropy in the diffusion rate for Xand has been applied to the refractive index profile reconstruction for single-mode optical channel waveguides. A sharp change in the index at the air–guide interface has been observed, as expected. The dependence of refractive index change on Ti concentration has been found to be nonlinear, such as quadratic, approximately.