Wavelength Dispersion of Ti Induced Refractive Index Change in LiNbO3 as a Function of Diffusion Parameters

Abstract

Z-cut X-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 (λ = 0.6328 μm, 1.1523 μm, 1.523 μm), between extraordinary and ordinary refractive index change Δne,o (z) and titanium concentration C(z) is found to be nonlinear and of the form: [formulla omitted] While αe,o is a constant, the proportionality coefficient Ae,odepends - not only on the wavelength X, but also on the diffusion conditions, characterized by Co, the Ti surface concentration of the diffused guide. Such a nonlinearity of Ti diffusion in LiNbO3 has been revealed thanks to a complete and wide range investigation on both indiffused Ti and index profiles. Copyright © 1987 by The Institute of Electrical and Electronics Engineers, Inc.