Producing channel waveguides requires a photolithographic mask, but the standard technique of using thermally evaporated metal films for proton exchange has proved to be unsuitable for withstanding the rather aggressive process of reverse proton exchange. We report the fabrication of a nonstoichiometric silica mask by ion-plating plasma-assisted deposition. This mask is strong enough to resist both direct and reverse proton exchange and is also compatible with anisotropic dry etching for patterning the mask and with electric field poling. Our technique is a practical alternative to the use of SiO2 sputtered masks.
© 2004 Optical Society of America
Original Manuscript: April 16, 2003
Revised Manuscript: September 16, 2003
Published: February 1, 2004
Antonino Parisi, Alfonso C. Cino, Alessandro C. Busacca, and Stefano Riva-Sanseverino, "Nonstoichiometric silica mask for fabricating reverse proton-exchanged waveguides in lithium niobate crystals," Appl. Opt. 43, 940-943 (2004)