Process for production of glass preform for optical fiber.

摘要

In order to provide an improved process for the production of a glass preform for an optical fiber which includes substantially no bubble therein and also have a substantially uniform shape, there is provided a process for the production of a glass preform which comprises at least silica for an optical fiber comprising producing a body comprising a rod on which fine glass particles are deposited preferably by the vapor phase reactions and heating the body to vitrify under a reduced atmosphere or a vacuumed atmosphere so that the glass preform is produced; in which process the heating comprises a first heating step of degassing the body at a first heating temperature, a second heating step of shrinking the body at a second heating temperature which is higher than the first heating temperature and which is lower than a third heating temperature, and a third heating step of vitrifying the shrunken body at the third temperature which corresponds to a vitrification temperature of the fine glass particles so as to produce the glass preform.