Optical fiber glass base material manufacturing method and optical fiber glass base material

Abstract

Provided is an optical fiber glass base material manufacturing method that includes flame polishing an outside of a starting base material that includes a core and a first cladding with an oxyhydrogen flame and then arranging a glass fine particle synthesis burner facing the starting base material, which rotates, moving the starting base material and the burner back and forth relative to each other along the starting base material, and depositing glass fine particles produced by hydrolysis of glass raw material in the oxyhydrogen flame as a porous glass layer of a second cladding, the method comprising synthesizing and depositing the glass fine particles under conditions in which a hydrogen flow rate during a first back and forth deposition pass performed immediately after supply of raw material is started is greater than a normal hydrogen flow rate.

Dependencies are inferred from the claim text.