Preparation and optical properties of sol-gel derived photo-patternable organic-inorganic hybrid films for optical waveguide applications

Photo-patternable TiO₂/organically modified silane hybrid films were prepared by combining a low-temperature sol-gel technique with a spinning-coating process. A ridge waveguide pattern was fabricated by ultraviolet light irradiation through a mask placed contact with the hybrid film in direct. Optical properties and photochemical activity of the hybrid film, including refractive index, thickness, propagation mode, and propagation loss, were studied and monitored by a prism coupling technique and Fourier transform infrared spectroscopy. The change of transmittance with exposure time was also observed by ultraviolet-visible spectroscopy. These results indicate that the hybrid film is potential application for fabrication of photonic devices by ultraviolet light irradiation. The structure of ridge waveguide pattern was characterized and studied by scanning electron microscope and surface profiler. The fabrication process of the as-prepared photosensitive hybrid film as compared with traditional binary mask has a great amount of advantages of cost-effective, simple, and smooth surface over non-photosensitive material methods.