| 摘要 |
PURPOSE:To prevent the production of a strain in the refractive index disbtribution of an optica fiber by growing soot of high purity silicon oxide while eliminating surface unevenness during deposition to deposit prescribed soot at a prescribed position. CONSTITUTION:A substrate 1 is rotated, and a high purity silicon compound, oxygen and an additive are fed from nozzles 2 to deposit soot 3 based on high purity silicon oxide on the substrate 1. Each nozzle 2 has a structure consisting of inner and outer pipes, and the silicon compound and the additive are fed from the inner pipe. The oxygen is fed from the outer pipe. The additive includes a compound of Ge or P. When the deposition of soot 3 reaches a prescribed amount, uneveness caused on the surface is eliminaed with a scraper 5 to flatten the surface, and the substrate 1 is lowered. When the surface of the deposited soot 3 shifts to the original position of the substrate 1, soot 3 is deposited on the surface again. By repeating this operation, a prescribed layer of soot 3 is formed. The layer is then converted into a transparent glass body by heating at a high temp. with a heater 4, and the body is spun to manufacture an optical fiber. |
