PRODUCTION OF BASE MATERIAL FOR OPTICAL FIBER

摘要

PURPOSE:To enable mass production of a base material for an optical fiber added with fluorine and to prevent the deterioration at the tip part of a multiple- pipe burner by strong heat by specifying the way of passing gases in said burner. CONSTITUTION:A blow-off port 7 for glass raw material, gaseous fluorine raw material and gaseous O2 is provided at the center and a blow-off port 8 for inert gas is provided to enclose said port; further a blow-off port 9 for gaseous H2 is provided to enclose said port. The reaction to synthesize the pulverous glass particles in the flame is thereby effected in the state of high O2 partical pressure. The decomposition of the gaseous fron in the flame and the reaction to synthesize the pulverous glass particles are effected satisfactorily and the efficient addition of fluorine is made possible. If the blow-off port for the gaseous H2 and the blow-off port of the gaseous O2 of the burner are adjacently provided, the oxyhydrogen flame is formed in the region extremely close to the outlet of the burner and therefore the tip part of the burner is strongly heated and is consequently deteriorated. Such deterioration is prevented by providing the part 8, not adjacently to said ports.