NONLINEAR-OPTICAL PROPERTIES OF PROTON-EXCHANGED WAVE-GUIDES IN Z-CUTLITAO3

Reflection second-harmonic generation from the polished waveguide end face is used to investigate the second-order nonlinear optical propert ies of as-exchanged and annealed proton-exchanged waveguides in z-cut LiTaO3. It is found that proton exchange results in a strongly reduced nonlinearity which, however, can be restored by thermal annealing. Se lective etching is used as a method to further investigate the structu ral changes following proton exchange and annealing. A correlation is found between the etching properties and the nonlinear optical propert ies. The results are discussed and related to the hydrogen concentrati on profile using a linear diffusion model for the anneal process.