摘要 |
PURPOSE:To effect high-speed and stable production of title matrix having specific refractive index distribution by a method wherein H2 flow rate is specifically controlled in production of optical fiber matrix by flowing various mixed gas of glass raw material and H2, etc. from plural nozzles. CONSTITUTION:From the center of five-layer coaxial burner 1, glass raw material 21 such as SiCl4 and H2 gas 22, glass raw material 23 such as GeCl4 and H2 gas 24, innert gas 25, H2 gas 26, and O2 gas 27 is flowed out. The gas undergoes hydrolysis and oxidation reaction to allow glass particles 3 to be stacked onto the starting material 4 which is rotating so that optical fiber base material 5 is produced. At this time, H2 gas flows 24 and 26 are changed and the flow rate of H2 gas 22 is controlled in the range of 50-300cc/min. This controls the particles body 5 in refractive index distribution and results in a high-speed stable production of optical fiber matrix 5 having a specified refractive index distribution. |