| 摘要 |
PURPOSE:To stably obtain the titled base material by making the flow rate of oxygen gas for reaction lower than that of starting material gases and feeding unreacted starting material gases into a quartz tube to remove moisture when a glass film is formed on the inside of the tube. CONSTITUTION:Starting material gases such as SiCl4, POCl3, GeCl4 and BBr3 and oxygen gas are fed into a quartz tube and heated from the outside of the tube to cause oxidation. The resulting quartz glass layer is deposited on the inner wall of the tube, and the tube is made solid by heating at a high temp. to manufacture an optical fiber base material. At this time, in order to prevent moisture adsorbed on the piping, etc. for the gases from being taken into the formed glass as OH groups causing transmission loss, the flow rate of the oxygen gas is made lower than that of the starting material gases, and unreacted starting material gases are fed into the quartz tube to remove moisture, e.g., according to the reaction of the equation. |
