TiO₂ waveguides thin films prepared by sol-gel method on glass substrates with and without ZnO underlayer

TiO₂ thin films have been deposited on glass substrates with and without ZnO underlayer by sol-gel dip coating process. XRD patterns show the formation of anatase phase with the diffraction lines (1 0 1) and (2 0 0) in TiO₂/glass sample. In TiO₂/(ZnO/glass) sample, TiO₂ is composed of anatase phase with the diffraction line (2 0 0) but the diffraction peaks of ZnO wurtzite are also well-defined. The determination of the refractive index and the thickness of the waveguiding layers has been performed by m-lines spectroscopy. The thickness of TiO₂ thin films deduced by Rutheford Backscattering Geometry (RBS) agrees well with that obtained by m-lines spectroscopy. TiO₂/glass sample exhibits one guided TE₀ and TM₀ polarized modes. In TiO₂/(ZnO/glass) sample, only, TE₀ single mode has been excited due to cutoff condition.