Photorefractive damage thresholds in Ti:LiNbO(3) channel waveguides

The photorefractive effect in titanium-in-diffused LiNbO(3) waveguides is studied both experimentally and theoretically. Measurements of mode size and transmitted optical power as a function of input optical power are presented. The diffusion constants in the diffusion model and the unknown parameters in Kukhtarev's model are determined from measurements of the near-field intensity profiles at low and at high intensity levels. These parameters can then be used to predict waveguide behavior as a function of the input power level. The simulated behavior closely resembles that observed experimentally. Calculated corrections for thermally induced index perturbation show that the thermal effects are higher-order corrections to the dominant photorefractive effect.