| 摘要 |
PURPOSE:In the production of a parent material for optical fiber mainly consisting of SiO2, the core tube for the oven has the innermost layer of quartz and the atmospheric gas contains SiF4 in the reaction system whereby a parent material of high quality for optical fiber is obtained with reduced contaminants and moist. CONSTITUTION:The supporting rod 2 is hung in the core tube 3 of SiC, mullite or alumina coated on its innermost lyaer with quartz of about 0.1mm thickness. The oven is heated at 1,200-1,300 deg.C with heating elements 4 simultaneously, the vapor of SiCl4 or SiO(CH3)4 is mixed with an oxygen gas and introduced into the core tube 3. At this time, a mixture of SiF4 and He is fed to form the parent materal for optical fiber, on the rotating support 2, which includes markedly reduced impurities such as Cu and moist, contains F so that the refractive index is adjustable and is mainly composed of SiO2, with largely prolonged life of the core tube 3. |
