Modelling Ti in-diffusion in

Abstract

This work presents theoretical results on the modelling of Ti in-diffusion in assuming the Ti activation energy to be spatially dependent along the diffusion depth direction as consequence of the Li concentration depletion due to its out-diffusion. The model also considers that Ti diffusion occurs as an ion exchange process in which ions substitute ions located in Li sites. The resulting diffusion equation is numerically solved according to initial and boundary conditions chosen to describe as close as possible the experimental scenario. The results show that this approach leads to highly asymmetrical Ti concentration profiles within the crystal, as already determined experimentally.

Design Methodology for Ti:LiNbO3 Waveguides

“…Recently, the diffusion process for Ti in LiNbO 3 was modelled considering that the diffusion coefficient, DðTÞ, depends on the concentration 17,18) and that the activation energy depends on the diffusion depth; 19) such a model allowed the explanation of the anomalous lateral penetration found in channel waveguides. 20) However, for diffusion in one dimension, assuming that DðTÞ is concentration independent, a simplified model can be obtained, allowing a satisfactory explanation for the experimental results.…”