| 摘要 |
PURPOSE:To enable the deposition and formation of a glass layer having excellent characteristics in high efficiency, by keeping the gas pressure in a glass pipe and the gas temperature in plasma within specific ranges, reacting the glass raw material gases with each other, and vitrifying the reaction product. CONSTITUTION:The gas pressure in a high-purity quartz glass pipe 1 used as the substrate is maintained to 5-20Torr with an evacuation system 6 while supplying the main material SiCl4, a fluorine-based doping material C2ClF5 and O2, etc., from the raw material feeding system 5 to the quartz glass pipe 1. Plasma 2 is generated by the plasma generator 3 using a microwave oscillator 4, and the plasma is reciprocated along the length of the pipe 1 at a high speed (5-10m/min) or a low speed (50cm/min). The gas temperature in the plasma is maintained to 800-1,200 deg.C to effect the oxidization and vitrification of the material. A glass layer is deposited on the inner wall of the pipe 1 to form a clad glass for optical fiber. |
