| 摘要 |
PURPOSE:To form a porous glass preform having a desired refractive index distribution with high reproducibility by controlling and setting conditions for manufacturing an optical fiber base material in accordance with the amounts of refractive index distribution prescribing reactive substances detected. CONSTITUTION:In order to detect a change or a fluctuation of a matrix caused by the characteristics of a burner, the flow rates of flame forming gases, the concns. of chlorides as glass starting materials, etc., the amounts of SiO2, a Ge component and OH groups are directly detected by different detecting methods. In order to regulate a change or a fluctuation of the matrix, the flow rates and blending ratio of glass starting materials such as SiCl4 and GeCl4, gases for forming a flame such as an oxyhydrogen flame and a carrier gas are controlled or the position of the burner is controlled. Some of them may be controlled at the same time. Thus, predetermined manufacturing conditions are set to form a porous glass preform having a desired refractive index distribution. |
