Waveguide properties of TiO₂/ORMOSIL composite thin films prepared by sol-gel processing on III-V compound semiconductor substrates

TiO₂/organically modified silane(ORMOSIL) optical waveguide thin films have been prepared at low temperature by the sol-gel technique by using y-Glycidoxypropyltrimethoxysilane and tetrapropylorthotitanate as precursors. Atomic force microscopy has been used to characterize the morphology and structural properties of the waveguide films. Waveguide properties of these composite thin films on III-V compound semiconductor substrates such as their refractive index, thickness, and propagation loss have been studied. It was experimentally demonstrated that grating structures could easily be fabricated for these composite thin films by using the embossing technique and we have successfully fabricated the grating by this method without baking. It was found that this method is specifically useful for the fabrication of diffractive grating and optical planar waveguides on sol-gel derived glass film coated on temperature sensitive substrates such as III-V compound semiconductors. As a preliminary result, the ridge waveguide and grating with a period of 1.102 μm and depth of 57.2nm have been successfully fabricated.