Method for producing glass preform for optical fiber.

摘要

A method for producing a glass preform for use in fabrication of an optical fiber, which comprises steps of forming a glass soot preform (1) from a glass-forming raw material, optionally heating the soot preform (1) under reduced pressure at a temperature at which the soot preform (1) is not vitrified, heating the soot preform (1) in an atmosphere comprising at least one fluorine-containing compound under reduced pressure or a pressure not lower than atmospheric pressure if the soot preform has been heated under the reduced pressure in the previous step, or under reduced pressure if the soot preform has not been heated in the previous step, and vitrifying the fluorine-added preform for a sufficient time to vitrify it, by which a glass preform having substantially no bubble therein and containing a sufficient amount of fluorine.