Silicon oxynitride films on fused silica for optical waveguides

We have evaluated chemical vapor-deposited silicon oxynitride films on fused silica as a potential integrated optics medium. Refractive index of these glassy films depends on composition, which is adjusted by controlling the ratio of the nitric oxide and silane reactants. Films of n = 1.48-1.54 had losses <0.4 dB/cm at 633 nm. The preparation of the fused silica substrate surface and other precautions to minimize scattering centers ape discussed.