Sol-gel preparation of thin films for integrated optics

The sol-gel process may be considered a method for producing glass and ceramic materials from metallorganic precursors by low temperature polymerization reactions. The process represents a powerful tool for making almost all kinds of transparent materials with interesting optical and photonic properties. In this paper, we present the experiments performed for the synthesizing of materials for optical applications in the 780, 1300 and 1500 nm range (waveguides, micromirrors, transducing layers for waveguide-based gas sensors). The correlation between the method of preparation and optical properties of two types of basic materials for thin films: monocomponent and binary materials (SiO₂, SiO₂-TiO₂, SiO₂-ZrO₂) was approached. Optical waveguides on silicon substrates were prepared using these materials. Also processes for porous layers doped with photochromic substances were developed. These layers offer many advantages over polymer films, for example, superior optical and mechanical properties and the ability to tailor film properties via the sol-gel fabrication process. We deposited these layers on channel waveguides to obtain chemical sensors with optical readout.