Fabrication of composite sol-gel optical channel waveguides by laser writing lithography

We report the preparation of high optical quality sol-gel waveguide films made from high titanium content organically modified silane (ORMOSIL) and the fabrication of optical channel waveguides in the deposited sol-gel films. The waveguide films were deposited on a solid substrate (such as silicon) by spin-coating and low temperature baking, and the channel waveguides were fabricated using laser writing and reactive ion etching (RIE). The properties of the sol-gel waveguide films were characterized using atomic force microscopy (AFM), ellipsometry, and UV-visible spectroscopy (UV-VIS). AFM and ellipsometry results showed that a dense and porous-free waveguide film could be obtained at the heat treatment temperature of 100 °C. The influence of the RIE parameters including O₂ content, rf power, and pressure on etching rate of the sol-gel waveguide films have been investigated. After a number of exploratory experiments, suitable etching parameters for the case of photoresist mask layer have been obtained.