Abstract

Thin film technique is needed for fabricating LiNbO₃ waveguide at relatively low temperature without doping any impurity. This method is expected to be effective in developing optical devices such as optical modulators, and SHG lasers. Thin film techniques investigated to data such as RF spattering^1,2 and laser ablation³ are based on direct epitaxial growth during deposition at high temperature. There are two problems associated with these methods. Firstly, deterioration of the crystal is unavoidable and pronounced when the film is thick. Secondly, fabrication speed is slow because the deposition rate is limited by the growth temperature. In this study, we developed a crystal-growth method obtained by post-annealing amorphous film deposited at room temperature. Our method is based on solid epitaxial growth and has the advantage of fabricating thick film without degradating the quality of the crystal as the film thickness increases. It also has the advantage of being quick to manufacture as we can prepare the base film at a high deposition rate and then make crystals in a relatively short time.

© 1993 Optical Society of America