| 摘要 |
PURPOSE:To simplify the process for production and to prevent the sticking of dust, etc., at the boundaries between respective layers by laminating at least two layers of quartz soot layers varying in deposition density on a substrate by a flame deposition method, then heating the substrate in a fluorine-contained atmosphere to vitrify the quartz soot layers. CONSTITUTION:SiCl4 is supplied at 110ml/min, O2 at 4l/min and H2 at 1.7l/min to an oxyhydrogen burneer and the quartz soot layer of 200mum thickness is formed on the Si substrate. In succession, the supply flow rates of the oxygen and hydrogen are changed to 5l/min O2 and 2.2l/min H2 and the quartz soot layer of 120mum thickness is formed. The substrate is heated for about one hour in gaseous SiF4 kept at 1,350 deg.C to simultaneously vitrify both quartz soot layers to form the quartz glass layer. The quartz waveguide having the two-layered structure is thus obtd. |
