METHOD FOR PRODUCING GLASS PREFORM FOR OPTICAL FIBER

摘要

The invention provides a rod-in-tube method for producing a glass preform for use in the fabrication of an optical fiber. The method comprises the steps of inserting a glass rod used as a core material into a glass tube used as a cladding material, fusing and closing one end of the cladding material, filling the gap between the core and cladding materials with an atmosphere containing at least one gaseous halogen-containing compound and then heating the core and cladding materials at a temperature not lower than 1,900.degree.C to collapse the gap between them and to fuse them together. Using the resulting glass preform, an optical fiber having low attenuation of light transmission can be fabricated.