Photorefractive non-linear single beam propagation in LiNbO3 waveguides above the optical damage threshold

Abstract The effect of photorefractive optical damage on single laser beams in undoped LiNbO 3 waveguides has been thoroughly investigated. The experiments have been carried out in soft proton exchanged planar LiNbO 3 waveguides covering a wide range of intensities (10–5000 W/cm 2 ). Different non-linear behaviours such as self-defocusing, beam break-up and temporal instabilities have been observed as the light intensity increases. X - and Z -cuts have been compared showing similar behaviours at low intensities although at higher intensities they present relevant differences. Some comments on the influence of these results in LiNbO 3 devices have been also included.