The issue of waveguide instability in LiTaO<sub>3</sub> is addressed. Changes in refractive index over time were monitored and used to compare the stability of waveguides fabricated by proton exchange, annealed proton exchange, Ti indiffusion, and Zn indiffusion. As opposed to waveguide formation in LiNbO<sub>3</sub>, all processes were found to produce unstable waveguides in LiTaO<sub>3</sub> crystals. It was concluded, therefore, that to eliminate completely the instability of waveguides fabricated in LiTaO<sub>3</sub> by using common fabrication techniques better growth procedures for this crystal may be necessary. Because of its extremely high melting point, current growth technology results in Li-deficient crystals that likely have a large number of defect sites and high strain values.
© 2002 Optical Society of America
(130.3130) Integrated optics : Integrated optics materials
(160.2100) Materials : Electro-optical materials
(230.2090) Optical devices : Electro-optical devices
(230.3120) Optical devices : Integrated optics devices
D. B. Maring, R. F. Tavlykaev, R. V. Ramaswamy, and S. M. Kostritskii, "Waveguide instability in LiTaO3," J. Opt. Soc. Am. B 19, 1575-1581 (2002)