| 摘要 |
PURPOSE:To obtain a glass article having a low content of impurities in heating a fine glass particle deposited material produced by VAD method in a core pipe and making the material transparent to give the glass article, by preforming a high-purity quartz glass layer on the inner surface of the core pipe. CONSTITUTION:Fine glass particles are deposited on the tip of a seed rod by VAD method to form a fine glass particle deposited material. Separately, a glass raw material gas is fed from a feeder 7 for the glass raw material gas into a core pipe 6 of a heating furnace device 4, fine glass particles formed by CVD method are deposited on the inner surface of the core pipe 6 to form a quartz glass layer 61. Then the fine glass particle deposited material is inserted into the core pipe 6 having formed the quartz glass layer 6, heated and made transparent to give a glass article. Consequently, the glass article not stained with impurities contained in the materials of the core pipe 6 can be produced and when the glass article is an optical fiber preform, optical fiber having excellent hydrogen-resistant characteristics is obtained. |
