APPARATUS FOR PRODUCING OPTICAL FIBER PREFORM AND METHOD FOR PRODUCING THE SAME

摘要

PROBLEM TO BE SOLVED: To provide a production apparatus capable of carrying out a rod in tube method in a properly reduced state of pressure. SOLUTION: The production apparatus for producing an optical fiber preform is provided with a jig 100 fixed to the upper end of a large-sized pipe 111 and a clamping part 200 for clamping the jig 100. The jig 100 comprises a cylindrical body having upper and lower openings 100a, 100b through which a primary preform 112 passes. The jig 100 is provided with a first hole 110 and a second hole 120 at the side face. The gap between the large-sized pipe 111 and the primary preform 112 is decompressed by differential evacuation between coarse evacuation from the first hole 110 and main evacuation from the second hole 120.