| 摘要 |
PURPOSE:To enable reduction in absorption loss of OH groups in of an optical fiber, by passing a dehydrating agent though a quartz tube in a dehydrating and transparent vitrifying step and following collapsing step of a porous SiO2 deposit layer deposited in the quartz tube in producing an optical fiber preform by a modified chemical vapor deposition method (MCVD). CONSTITUTION:An optical fiber preform is produced by the following steps (a)-(d). That is the steps of (a) depositing metallic oxide fine particles containing SiO2 on the inner wall of a quartz tube to form a porous deposit layer, (b) passing a dehydrating agent (e.g. SOCl2) through the quartz tube having the porous deposit layer to dehydrate the above-mentioned porous deposit layer, (c) transparently vitrifying the afore-mentioned porous deposit layer while passing the dehydrating agent through the quartz tube and (d) collapsing the quartz tube in a state filled with the dehydrating agent therein. |
