for active planar waveguides*

Sol-gel films of SiO2–TiO2-doped with Eu3+ or Er3+ ions were prepared by spin coating with a variety of molar concentration ratios of tetraethoxysilane (TEOS) and titanium isopropoxide (TPOT). The ratios of SiO2–TiO2 were 90/10, 85/15, 80/20, 75/25 and the concentrations of Eu and Er ions varied from 10–3 to 5⋅10–2 mol %. Silica–titania films annealed from 150 up to 900 °C decreased their thickness from 300 to 150 nm and increased the refractive index from 1.49 to 1.62. The multilayer (6–8 layers) silica–titania thin films with thickness of about 1.2–1.6 µm have been developed in order to make highly doped with Eu3+ or Er3+ planar waveguides on silicon substrates. Luminescence spectra, lifetimes as well as FTIR and micro-Raman spectra have been measured. The influence of active ion concentrations and annealing temperature on the luminescence properties and the structure of thin films were investigated