METHOD FOR PRODUCING GLASS PREFORM FOR OPTICAL FIBER

摘要

The invention provides a method for producing a glass preform comprising flame hydrolyzing a glass raw material in an oxyhydrogen flame to form fine glass particles of quartz, depositing the fine glass particles on a seed member to produce a solid or hollow cylindrical soot preform, at least a part of which contains GeO2, and heating and sintering the soot preform by introducing it into an atmosphere comprising an inert gas at least a part of which is kept at a temperature not lower than 1,600.degree.C at an introducing rate not smaller than 3 mm/min. An optical fiber having a longitudinally homogeneous composition and a low attenuation of light transmission can be fabricated from the glass preform produced by this method.