PRODUCING METHOD FOR GLASS PREFORM FOR OPTICAL FIBER

摘要

PROBLEM TO BE SOLVED: To provide a producing method for obtaining a high quality transparent glass body (glass preform for optical fiber) by dewatering and sintering GeO2 added glass fine particle deposits without reducing the amount of GeO2 . SOLUTION: The GeO2 added glass fine particle deposits are dewatered and sintered and, as the dewatering treatment, a process of heating the same at 1000 deg.C or more in GeO4 -containing atmosphere is included. Thereby, the dewatering is performed without reducing GeO2 content. The process is preferably performed at 1400 deg.C or less. In addition, when temperature-elevating heating is started in Cl2 and GeCl4 -containing inactive gas atmosphere and, over 1000 deg.C, GeCl4 -containing inactive gas atmosphere is used, a high dewatering efficiency is obtained. Therein, the sintering is performed in inactive gas atmosphere.