Waveguides in LiNbO<sub>3</sub> are realized by a soft proton exchange (SPE) process with use of a melt of stearic acid highly diluted by lithium stearate. No phase transitions are formed when α-phase waveguides are obtained by SPE. The α-phase presents the same crystalline structure as that of pure LiNbO<sub>3</sub> crystal, and it maintains the excellent nonlinear and electro-optical properties of the bulk material. The kinetics of the SPE method is studied by the use of secondary-ion mass spectrometry and prism-coupling techniques. The hydrogen effective diffusion coefficient as well as the self-diffusion coefficients of H<sup>+</sup> and Li<sup>+</sup> ions are determined as a function of the proton-exchange temperature for X-cut LiNbO<sub>3</sub>.
© 2001 Optical Society of America
(130.3130) Integrated optics : Integrated optics materials
Yu. N. Korkishko, V. A. Fedorov, E. A. Baranov, M. V. Proyaeva, T. V. Morozova, F. Caccavale, F. Segato, C. Sada, and S. M. Kostritskii, "Characterization of α-phase soft proton-exchanged LiNbO3 optical waveguides," J. Opt. Soc. Am. A 18, 1186-1191 (2001)