APPARATUS FOR SINTERING OPTICAL FIBER POROUS PREFORM

摘要

PROBLEM TO BE SOLVED: To provide an apparatus for sintering an optical fiber porous preform for cost effectively production of an optical fiber preform having excellent optical transmission characteristics by efficiently sintering the optical fiber porous preform and vitrifying this preform. SOLUTION: This apparatus for sintering the optical fiber porous preform includes at least a heating means and a furnace core tube and vitrifies the optical fiber porous preform by successively sintering the preform by the heating means within the furnace core tube. The diameter of the furnace core tube described above on the side (small-diameter side), where the vitrifying part 3b of the optical fiber porous preform 3 is housed, is smaller than the diameter of the furnace core tube on the side (large-diameter side) where the unsintered part 3a is housed.