Peculiarities of Photorefractive Response in Planar Waveguides Fabricated by Combined Proton and Copper Exchange

Abstract

In this work a photorefractive effect in proton-exchanged planar waveguides on LiNbO 3 crystals is discussed. These waveguides are doped by copper with the aid of a new technique using the low-temperature ionic exchange. The experimental investigation has revealed the anomalous character of the photorefractive response in strongly doped waveguides. Photorefractive measurements are made over a wide range of H +, Cu + and Cu 2+ concentrations, altered by a seriesof oxidation treatments caused by back ionic exchange. Fabrication parameters allowing the realization of high photorefractive sensitivity either in visible or near infra-red ranges are identified.