| 摘要 |
PURPOSE:To minimize the eccentricity of a core rod, by forming a heat flexible part bending by light heating on the base end side of a core rod, inserting the core rod into a clad quartz tube, aligning the axis of both utilizing the flexibility of the heat flexible part and heating and integrating the core rod with the clad quartz tube. CONSTITUTION:Part of the diameter on the base end of a core rod 1 is thinned to form a heat flexible part 8 bending by light heating. The resultant core rod 1 is then inserted into a quartz tube 2 and a tapered receiving part 12 of a dummy tube 3 is heated from the surface to integrate a tapered part 10 with the taper receiving part 12 so as to align the axis of the core rod 1 with the axis of the clad quartz tube 2 utilizing the flexibility of the heat flexible part 8. Both end parts of the clad quartz tube 2 are held by chucks 6 of a vertical glass lathe and hot collapsing is started from the part of the clad quartz tube 2 on the tip side of the core rod 1 by a collapsing burner 7 while rotating the clad quartz tube 2. Thereby, the total length is successively integrated to produce the aimed preform. |
