APPARATUS FOR PRODUCING OPTICAL FIBER BASE MATERIAL AND METHOD FOR PRODUCING OPTICAL FIBER BASE MATERIAL USING IT

摘要

PROBLEM TO BE SOLVED: To provide an apparatus for producing an optical fiber base material having a cylindrical core partition 13 around a core burner 1 of which the aperture is at a core burner side in a reaction vessel for VAD method. SOLUTION: An up flow gas caused by a core flame or a clad flame is varied to a turbulent down flow pushed by a down flow gas and to the up flow by being struck to the reaction vessel wall. As core flame flickering comes to bigger, a glass glowing velocity is unstable and the optical fiber base material obtained is lack of uniformity. As the top temperature of a soot comes to not uniform and the soot density at the top part is lowered, crack is easy to be caused on the soot.