Characteristics of effused slab waveguides in LiNbO3

Abstract
Concentration profiles for LiNbO3 surface optical‐waveguiding layers formed by diffusion‐controlled evaporation of Li2O are calculated on the assumption that the evaporant flux is small and proportional to the available lithium ion concentration at the surface. The calculated profiles are found to agree reasonably well with the index‐of‐refraction changes observed by Kaminow and Carruthers. The apparent concentration dependence of the diffusion coefficient is discussed qualitatively. Approaches to design of waveguiding layers of specified characteristic are described.