In this paper the influence of RF power, ammonia flow, annealing temperature, and annealing time on the optical and mechanical properties of plasma-enhanced chemically vapor deposited silicon oxynitride films, is presented. A low refractive index (1.47 to 1.48) film having tensile stress has been developed as cladding material for optical waveguides. By combining this waveguide material with a special type of UV photosensitive glass, a low tensile stress strip-loaded waveguide structure, based on a three-layer sandwich structure, has been designed and the stress distribution through the structure investigated.