MANUFACTURING APPARATUS FOR POROUS GLASS PREFORM AND GLASS PREFORM FOR OPTICAL FIBER

摘要

A manufacturing apparatus for a porous glass preform, comprising a glass particulate deposition burner repeating reciprocating motion along the longitudinal direction of a base material glass bar being rotated on its axis and an exhaust gas hood repeating reciprocating motion in synchronism with the burner which is installed above a porous glass soot formed of deposited glass particulates. The angle (theta) of the exhaust gas hood covering the porous glass soot is 100° or higher relative to the axial center of the porous glass soot. Also, where the offset amount of the center axis of the burner to the center axis of an exhaust gas tube is (r), the ratio (r/R) thereof to the radius (R) of the exhaust gas tube is larger than 0 and equal to or less than 1.5.