Fabrication of planar optical waveguide material on silicon by flame hydrolysis deposition

SiO2 thick films were deposited on silicon wafer (2 inches in diameter) as buffer layer for fabricating planar optical wave-guide by flame hydrolysis deposition (FHD) method. The deposition speed is as high as 8μ+m per minute. Then the deposited films were consolidated in electric furnaces in vacuum or air ambience at the temperature of 1380°C. As a result, transparent vitreous silica (or called silica glass) and semi-transparent cristobalite films were obtained. The thickness of the vitreous silica films is up to 40μm, and this kind of films is suitable for buffer layer of planar wave-guide. SiO2 thick films doped with GeO2 were obtained by the same process to fabricate the core layer. Finally, several factors affecting the consolidated silica films were discussed in detail.