METHOD FOR REMOVING STARTING QUARTZ TUBE OF PREFORM ROD

摘要

PURPOSE:To remove the quartz tube in a short time by placing a preform rod including a starting quartz tube in an SF6 atmosphere and vaporizing the quartz tube by heating. CONSTITUTION:A core rod 3 is inserted into a starting quartz tube 1 provided with a clad layer 2 at the inner peripheral wall surface. The tube 1 and the clad layer 2 are softened and united to a body by heating the outer periphery of the quartz tube 1 to obtain a preform rod. 4. The rod 4 is placed in an SF6 atmosphere and heated to allow the quatz tube 1 to react with SF6. And the quartz tube 1 is vaporized into SiF6 which is discharged from an outlet 5B. According to said process, the starting quartz tube 1 is removed in a short time and further without generating any cracks.