Direct laser writing of ridge optical waveguides in silica-titania glass sol-gel films

Sol-gel process is attracting a growing attention as a rather simple technology with potential for low-cost batch manufacture of integrated optical waveguides. Here experimental results are presented on the fabrication of silica-titania sol-gel films and on their laser densification, a technique which may be very useful for rapid circuit prototyping. Transversally multimode waveguides with propagation loss around 1 dB/cm have been produced by selective densification using a CO2 laser. Data from optical and structural analysis of the sol-gel strips are reported and discussed.