| 摘要 |
PURPOSE:To manufacture the title base material with little transmission loss and little OH group absorption loss by feeding a dehydrating agent into a glass tube in a process for depositing a glass fine particle layer on the inner wall of the tube or after the process to make the layer transparent under an adjusted internal pressure of the tube. CONSTITUTION:Quartz tube 4 supported by chucks 5 is rotated, starting material gas is introduced into tube 4 from supply section 1, and simultaneously a dehydrating agent such as SOCl2 is introduced into tube 4 from halide introduction section 2 after being bubbled with O2 gas. Oxyhydrogen burner 6 is run from starting material supply side 1 to magnet valve 8a side 8 to heat tube 4, whereby the starting material gas is oxidized to deposit a glass fine particle layer for a clad on the inside of tube 4, and simultaneously it is hydrolyzed. This process is repeated suitable times. Glass fine particles for a core are similarly deposited, and the temp. of tube 4 is raised with burner 6 to perform transparent vitrification while preventing shrinkage deformation of tube 4 by adjusting the internal pressure of tube 4 to a value slightly higher than the atmospheric pressure. Tube 4 is then made solid similarly to obtain an optical fiber base material. |
