CHARACTERIZATION OF PHOTOREFRACTIVE LINBO3 WAVE-GUIDES FABRICATED BY COMBINED PROTON AND COPPER EXCHANGE

Photorefractive planar waveguides in LiNbO3 are fabricated by a combined proton and copper exchange. The dependence of refractive index profiles, optical absorption, and electrooptic coefficients on different fabrication steps is investigated. With holographic methods dark and photoconductivity, holographic sensitivity, and light-induced refractive index change in the waveguides are measured. By the additional copper exchange the steady state diffraction efficiency of holographic gratings in our proton-exchanged waveguides is increased from 0.01 to 65%.