Optical waveguides in LiTaO_3: silver lithium ion exchange

Silver lithium ion exchange has been found to produce optical waveguides in x-cut LiTaO(3)at temperatures well below the Curie temperature, producing waveguides that require no repoling. This process is attractive for integrated optics because LiTaO(3) is less susceptible to optical damage and has much lower birefringence than the more commonly used LiNbO(3) substrate. The exchange process has been studied as a function of temperature. Diffusion coefficients, activation energy, losses, and temperature dependence of the extraordinary index change are given. Index increases of Deltan(e) ~ 0.03-0.05 at lambda = 632.8 nm and losses of 0.8-1.3 dB/cm for the TE(O) mode are comparable with values for Ti-diffused guides in LiNbO(3), making this technique potentially useful for integrated optics applications.