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

Photorefractive planar waveguides in LiNbO3 are fabricated by a combin ed proton and copper exchange. The dependence of refractive index prof iles, optical absorption, and electrooptic coefficients on different f abrication steps is investigated. With holographic methods dark and ph otoconductivity, 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 grati ngs in our proton-exchanged waveguides is increased from 0.01 to 65%.