The refractive index and optical attenuation of sputtered SiO2–Ta2O5 waveguide film were measured in the 0.633-1.32-µm wavelength region. The waveguide film had a large refractive-index range of 1.46–2.08, which can be adjusted by suitable selection of the composition ratio of the SiO2–Ta2O5 target. Substrate heating, up to 270°C, during the sputtering process was effective for obtaining low attenuation. The waveguide films showed low attenuations, <0.41 dB/cm for the TE° mode. The best fits of the form λ γ to the measured attenuation have γ between 0 and -1, where λ is the wavelength. This wavelength dependence of the attenuation can be interpreted based on mode conversions due to the film surface roughness.
© 1983 Optical Society of America
Mario Kobayashi and Hiroshi Terui, "Refractive index and attenuation characteristics of SiO2-Ta2O5 optical waveguide film," Appl. Opt. 22, 3121-3127 (1983)