Sol-gel fabrication of GeO₂/ormosils organic-inorganic hybrid material channel waveguides

A GeO₂/γ-glycidoxypropyltrimethoxysilane hybrid material obtained by a low temperature sol-gel method was studied in an optical slab waveguide configuration. Influence of the germanium content and heat treatment temperature on the optical properties of the waveguide thin films deposited on quartz substrates was characterized by atomic force microscopy and UV-visible spectroscopy. The obtained results indicate that macro-pore free and low absorption in the visible range waveguide thin films could be obtained at a heat treatment temperature below 300 °C. A strong UV absorption region at short wavelength ∼ 200 nm, accompanied with a shoulder peaked at ∼ 240 nm, was identified. The propagation modes, loss properties, refractive index, and thickness of the planar waveguide thin films were investigated by a prism coupling technique. It has been experimentally demonstrated that a channel waveguide structure could easily be fabricated from these hybrid sol-gel thin films by using reactive ion etching.