| 摘要 |
PURPOSE:To eliminate the need for axial alignment and to obtain an optical fiber of high quartz type advantageously by charging raw materials for clad glass into a tubular rotary vessel to be gelled and charging raw materials for a core therein to form a preform which is gelled in one body. CONSTITUTION:Sol liquid 2 of raw materials for clad glass are transferred into a cylindrical vessel 1, and the vessel 1 is rotated to form a cylindrical clad gel 3 on the inside wall surface of the vessel 1. Thereafter, sol liquid 4 of raw materials for core glass are transferred into the clad gel 3' and the vessel 1 is rotated to form a core gel 5 in tight contact with the gel 3''. This core-clad gel preformed in one body is dried to a dried gel 6 to be sintered in an electric furnace or the like and to obtain a hollow preform. The preform is solidified in an electric furnace or the like to be drawn and to obtain an optical fiber consisting of the core and the clad. According to this method, the production of large- sized preforms is made easy and free selection for raw materials is made possible. |
