SiOx buffer layer is widely employed in metal-clad Z-cut LiNbO3 optical waveguides to prevent excessive propagation loss and disturbances induced by the direct loading of the metal on the guiding layer. The dependence of propagation loss in proton-exchange LiNbO3 channel waveguides induced by a SiOx buffer layer on the annealing time is studied using a nondestructive measurement method. These studies reveal that the propagation loss is degraded for annealing times of less than 3 h, while it can be improved by about 0.08 dB/cm for annealing times longer than 6 h. By extending the annealing time to 8 h, we demonstrate a propagation loss reduction of 0.09 dB/cm. The physical mechanisms, including surface roughness, refractive index changes, oxidation of the SiOx buffer layer, optical confinement, and surface scattering of the LiNbO3 channel waveguide are also investigated.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)