FURNACE AND METHOD FOR MANUFACTURING OPTICAL FIBERS PREFORM USING MODIFIED CHEMICAL VAPOR DEPOSITION

摘要

A furnace and a method for manufacturing an optical fiber preform by MCVD(Modified Chemical Vapor Deposition) are provided to effectively cut off the external air from flowing into the front end of the electric furnace by increasing the supply amount of inert gas if the electric furnace moves fast, thereby repressing oxidation of a heating element and extending the life time of the heating element and the electric furnace. An electric furnace for manufacturing an optical fiber preform by MCVD is composed of an inlet port(110) through which a quartz tube(1) is inserted; an outlet port(120) through which the quartz tube is discharged; gas passages(130,130') for making the inert gas flow into the electric furnace; a heating element(200) for surrounding the quartz tube and containing the quartz tube; and a flow regulating unit(400) connected with the gas passage to increase or decrease the flow of the inert gas flowing through the gas passage, according to the progressive direction and speed of the electric furnace.