| 摘要 |
PURPOSE:To improve productivity and quality at low cost by depositing glass fine particles generated by flame hydrolysis of Si compounds on the outer periphery of a prescribed starting material and heating and directly melting it by oxyhydrogen flames to make it transparent glass. CONSTITUTION:Glass fine particles as a gaseous starting material are generated by subjecting starting compounds for glass to flame hydrolysis in oxyhydrogen flames. A porous glass preform consists of a core or clad obtained by depositing the glass fine particles on a carrier, such as a quartz glass bar is made dehydrated transparent glass to obtain a starting material 1 which is a transparent quartz glass preform for optical fiber of outer diameter 1.5-8 times larger than the core diameter. Next, SiCl2 as the gaseous starting material, GeCl4 of dopant, O2 and H2 are fed from an oxyhydrogen flame burner 2 at the outer periphery of the starting material 1 to subject SiCl4 an GeCl4 to flame decomposition in the flames, causing Si fine particles and germanium oxide particles to be generated and deposited to obtain a core 4. Next, silica particles generated by burners 5, 7, 9 are deposited and made transparent to produce a glass preform for optical fiber. |
