Experimental investigations of the photorefractive damage in pure PPLN waveguide

Photorefractive damage in pure PPLN waveguides occurs during the SHG process and is an undesirable effect because it decreases the SHG efficiency. In this work we investigated the photorefractive response in periodically poled waveguide structures using an interferometric method. The modulation of the refractive index depends on temperature, input intensity and wavelength of the laser beam. The magnitude of the induced refractive index modulation can reach values in the order of 10e-5. The obtained experimental results offer the possibility to control the SHG process via the photorefractive effect or to realize different coupling processes in pure PPLN waveguide arrays.