Planar optical waveguides fabricated using organic-inorganic hybrid sol-gel materials for optical interconnection and waveguide devices

Ridge and buried channel waveguides were fabricated on different substrates such as SiO₂-on-Si, Si, glass wafers and PCBs by a sol-gel processing together with a photolithography process using photopatternable hybrid solgel materials. Thick sol-gel films of up to 100 microns were developed using a modified sol-gel process and ridge waveguides; with vertical smooth sidewalls were obtained. The refractive index of the coatings can be varied in a large range by modifying some components of the sol-gel precursor while the coating quality was retained. Waveguide coupling of 633 nm red laser was realized with an end-face direct fibre coupling setup.