Method of forming a porous glass preform by vapour phase deposition

摘要

A method of forming a silica soot preform comprising: forming a primary soot preform (102) on an outer periphery of a glass rod (101) by a primary burner (104); and forming a secondary soot preform by a secondary burner (103) on an outer periphery the primary soot preform, wherein a diameter of the primary soot preform is set to be ranged from twice to five times of a diameter of the glass rod, a thickness of the secondary soot preform is set to be range from 1.5 times to seven times of that of the primary soot preform. Consequently, the deposition rate with respect to the introduction of the raw material gas is considerably increased. Further, it is possible to maximize a performance of depositing the primary soot preform.