METHOD FOR SINTERING POROUS-GLASS MATERIAL, METHOD FOR MANUFACTURING PREFORM AND OPTICAL FIBER, AND POROUS-GLASS MATERIAL

摘要

A method for sintering a porous-glass material to form a glass base material, which is a base material for an optical fiber, comprising: preparing a ring heater having an opening, through which the porous-glass material passes, for heating the porous-glass material;selecting the porous-glass material having an outer diameter (d) within a predetermined range, the predetermined range being determined based on an inner diameter (D) of the opening of the ring heater; and heating the porous-glass material in an atmosphere of dehydration gas and inert gas with the ring heater.