Wavelength dispersion of Ti induced refractive index change in LiNbO3as a function of diffusion parameters

-cut -propagating, LiNbO3:Ti planar waveguides have been characterized over a wide range of diffusion conditions. Measurements of Ti concentration and refractive indexes have revealed Gaussian profiles. Their dependence with diffusion conditions have been studied. The relation, established at several wavelengths ( m, 1.1523 μm, 1.523 μm), between extraordinary and ordinary refractive index change and titanium concentration is found to be nonlinear and of the form: While is a constant, the proportionality coefficient depends not only on the wavelength λ, but also on the diffusion conditions, characterized by C0, the Ti surface concentration of the diffused guide. Such a nonlinearity of Ti diffusion in LiNbO3has been revealed thanks to a complete and wide range investigation on both indiffused Ti and index profiles.