METHOD FOR PREPARING OPTICAL WAVEGUIDE FILM

摘要

PURPOSE:To improve transmission of optical waveguide film by depositing fine particles of glass from a flame burner on a silicon substrate precovered with an oxidized film to form a porous glass fine particle layer and then heating the porous glass fine particle layer while adding fluorine to make the layer transparent. CONSTITUTION:An Si substrate to deposit glass fine particles is placed on a turn table in a reactor. A deposited face of glass fine particles on the Si substrate on the turn table having a heater embedded in the interior is maintained at about 600 deg.C. The turn table is rotated while piling the glass fine particles from a flame burner, the flame burner is reciprocated in the direction of its mobile diameter direction to uniformly deposit the glass fine particles. The surface of the substrate is coated with an oxidized film having >=2mum thickness so that Si constituting the substrate will not be reacted with SiFe for adding fluorine. The oxidized film is formed by thermal oxidation. Then the glass fine particles are heated in an atmosphere of a mixed gas of a raw material gas of fluorine and 1-80vol.% O2 gas based on the raw material gas in an electric furnace and made transparent.