| 摘要 |
PURPOSE:To produce a base material for an optical fiber in a short time, by inserting a hollow cylindrical glass pipe with a low OH content into the hollow of a material glass pipe. CONSTITUTION:Into a material glass pipe 1 is inserted a hollow glass pipe 2 with an OH content of as low as few ppms. By externally heating the pipe 1 to a temperature higher than the softening point, the pipe 1 is lined with the pipe 2 to form a second material glass pipe. Into the second material glass pipe is passed a mixture prepared by mixing a material gas of a main component and a material gas of oxides so as to provide a refractive index designed for a clad, and the mixture passing is heated to a temperature of 1200-1600 deg.C by an external heat source. By this heating, the mixture deposits and vitrifies, forming a clad. Next, into the clad is passed a mixture prepared by mixing a material gas of a main component and a material gas of oxides so as to provide a refractive index designed for a core, and the mixture passing is heated by an external heat source. By this heating, the mixture deposits and vitrifies, forming a core. The pipe is heated to a temperature higher than 1600 deg.C to effect collapsing of the hollow. |
