PROTON-EXCHANGED WAVE-GUIDES IN LINBO3 AND LITAO3 FOR INTEGRATED LASERS AND NONLINEAR FREQUENCY-CONVERTERS

We present a review of our research activities concerning the proton e xchange technique on lithium niobate and lithium tantalate for integra ted lasers and nonlinear frequency converters. In the first part we pr esent the material characterizations that allowed us to establish the phase diagram of the proton exchanged layers on both crystals. In the second part we show how the knowledge of these phase diagrams allows u s to understand and handle the problem of the reduction of the excited -state lifetime of the rare-earth ions in Nd- and Er-doped crystals. I n the third part, we describe the influence of the different proton ex change processes on the nonlinearity and the domain structure of perio dically poled crystals, which leads us to recommend the use of wavegui des fabricated using low-acidity melts, which preserves both the nonli near coefficient and the domain structure. (C) 1998 Society of Photo-O ptical Instrumentation Engineers.