| 摘要 |
PURPOSE:To obtain a base material for optical fiber wherein a preform nearly free from scattering loss of light is produced by allowing denaturing treatment gas for the surface of glass to flow through the gap of a glass tube and a glass rod and also heating them at high temp. CONSTITUTION:In such a case that a quartz glass tube is heated by a burner from the outside while being rotated and gas for forming the cladding is passed to the inside of the quartz glass tube and a cladding layer is formed on the inner surface thereof and thereafter a quartz glass rod is inserted and provided and both the glass tube and the glass rod are integrally fused to produce a base material for optical fiber, the following treatment is performed. Before the above-mentioned fusion into one body, denaturing treatment gas for the surface of glass is allowed to flow through the gap of the glass tube and the glass rod and also these are heated at high temp. and thereby the surfaces of the glass tube and the glass rod are subjected to denaturing treatment. Further, as the above-mentioned denaturing treatment gas for the surface of glass, gas contg. >=80vol% chlorine is used. |
