Channel Optical Waveguides with Spatial Longitudinal Modulation of Their Parameters Induced in Photorefractive Lithium Niobate Samples

Abstract

The influence of point-by-point exposure of lithium niobate sample surface, doped with photorefractive impurities, to the longitudinal modulation of refractive index inside the formed waveguide channel is experimentally studied using optical probing method. Formation of channel waveguides by laser beam in different directions with respect to the crystal optical axis has been demonstrated. The channel waveguides have been formed via the point-by-point exposure at light wavelengths of 532 nm and 450 nm. Variation of distance between exposing light spot centres demonstrates the possibilities of optical inducing of longitudinally homogeneous and inhomogeneous channel waveguides.