Imtiaz Ahmad TAJ, Ping XIE¹, Kojiro KOYANAGI² and Teruhito MISHIMA²

Communication Enabling Technologies, 5-A, Constitution Avenue, Islamabad, Pakistan
¹Institute of Physics, Chinese Academy of Sciences, Beijing 100080, China
²Division of Electronics for Informatics, Hokkaido University, North-14, West-8, Sapporo 060-0814, Japan

(Received June 23, 2003; Accepted May 24, 2004)

We carried out detailed calculations for photorefractive wave-mixing switches based on one of three crystals with high electro-optic coefficients, namely, BaTiO₃, Strontium Barium Niobate (SBN (0.75)), and Potasium Sodium Strontium Barium Niobate (KNSBN). A comparison of results for the three crystals shows that a 0^°-cut BaTiO₃ crystal is suitable for a longitudinal switch and requires a voltage of about 80 for a 2-mm-thick crystal to induce sufficient phase mismatch. The electrodes must be transparent for the incident and diffracted beams. A 45^°-cut SBN (0.75) crystal, however, is suitable for a lateral switch and requires a voltage of about 150 for a 1-mm-wide crystal. The electrodes do not need to be transparent.

Key words: photorefractive, four-wave mixing, optical switch, longitudinal and lateral switches, Pockels effect, BaTiO₃, SBN, phase mismatching