APPARATUS FOR PRODUCING OPTICAL FIBER PREFORM

摘要

PURPOSE: To make it possible to surely prevent the infiltration of unreacted soot into an upper cylinder without stirring the gases in a reaction vessel even if the bore of the upper cylinder of an apparatus for producing an optical fiber preform is made sufficiently large in order to improve the quality of the optical fiber preform. CONSTITUTION: This apparatus 1 for producing the optical fiber preform is obtd. by mounting the upper cylinder 3 onto the reaction vessel 2 of a box shape and is provided with a driving device for pulling up the formed cylindrical soot S, while rotating the formed soot of cylindrical shape, to the upper past of the upper cylinder 3. A spacer 4 is interposed between the reaction vessel 2 and the bottom end of the upper cylinder 3. The apparatus for producing the optical fiber preform is provided with a gap communicating to the outside between the reaction vessel 2 and the bottom end of the upper cylinder 3.