PROCESS FOR PRODUCING AN OPTICAL FIBER PREFORM AND APPARATUS THEREFOR

摘要

A process for producing an optical fiber preform in a muffle furnace by hydrolyzing a gaseous glass forming material with a flame from an oxyhydrogen burner and depositing the resulting soot in a rod shape and an apparatus therefor are described, wherein a gas is supplied to the muffle furnace other than from said burner, and the volume supply of said gas is held constant by controlling the amount of a control gas supplied into an intermediate portion of all exhaust pipe through which the gases formed in the muffle furnace and the fine glass particles that do not deposit in a rod shape are discharged.