Microscope Raman scattering and X-ray diffraction study of near-stoichiometric Ti:LiNbO ₃ waveguides

The crystalline phase within guiding layers of near-stoichiometric strip and planar Ti: LiNbO ₃, waveguides, prepared by the method of simultaneous work of vapour transport equilibration (VTE) treatment and indiffusion of Ti film, was studied by combined confocal microscope Raman scattering and X-ray powder diffraction. The results show that the strip and planar waveguide layers still retain the LiNbO ₃ phase and no other non-LiNbO ₃ phases can be identified within the guiding layer. Li/Nb ratios inside and outside the strip and planar waveguide layers were determined from the microscope Raman scattering results and compared to those obtained from the measured optical absorption edge. It is shown that the Li/Nb ratios are homogeneous within the waveguide layer and are close inside and outside the waveguide layer.