Phase composition and stress in LiTaO ₃ proton-exchanged optical waveguides

Abstract

The phase composition of the top layer of Li1−xHxTaO3 waveguide layers produced at different modifications of the proton exchange (PE) technology has been analyzed based on their IR reflection spectra. These spectra contain new bands within the range , each phase having its own reflection spectrum. Since the top layer is actually the strongest proton-exchanged one of all sublayers building the waveguide layer, the recognition of the top sublayer's phase in many cases could be used to make conclusions about the phases building the rest of the entire PE layer. The intrinsic stress caused by crystal lattice deformation due to the PE was calculated by an optical integral method. An attempt to explain the level of stress is made based on the phase composition of the studied samples.