SILICA-BASED SOL-GEL OPTICAL WAVE-GUIDES ON SILICON

Silica-based waveguiding layers are readily obtained by the spin-coati ng of appropriate sols on silicon wafers. They may easily be doped wit h rare earth elements, for intended applications such as lasers or amp lifiers. The authors describe the preparation and characterisation of such films. The film structure was investigated by X-ray photoelectron spectroscopy (XPS), X-ray absorption spectroscopies (NEXAFS and EXAFS ) and Fourier transform infrared spectroscopy (FTIR). Their surface ar ea, evaluated by Brunauer-Emmett-Teller (BET) analysis, and their poro sity, estimated from refractive index measurements, are reported. Fina lly, rare earth fluorescence lifetime data are presented and interpret ed.