Characterization of vapor diffused Zn:LiTaO/sub 3/ optical waveguides

Diffusion and optical properties of planar waveguides produced in LiTaO/sub 3/ by a recently developed technique that utilizes Zn diffusion from vapor phase are presented. The waveguides are obtained by 6-h diffusion at temperatures as low as 800 degrees C. The results indicate that Zn is a fast diffusant in LiTaO/sub 3/ and has activation energies that are slightly less than those for Ti diffusion into LiTaO/sub 3/. The diffusion temperatures for Zn are much lower than the 1150-1200 degrees C require for Ti metal indiffusion. The diffusion coefficient of Zn at 800 degrees C, is comparable to that of Ti at 1200 degrees C. The resulting waveguides support both ordinary and extraordinary modes of polarization. The low temperature diffusion slows out diffusion and has been shown to be advantageous for making low-loss optical waveguides in LiTaO/sub 3/.>