PRODUCTION OF PARENT MATERIAL FOR OPTICAL FIBER

摘要

PURPOSE:The swing circulation at the top and bottom of the porous glass growing part on the sintering rod is adjusted so that the axis of the growing part is allowed to coincide almost with the rotation center of the rotation chuck whereby porous glass grows on the center axis of the optical fiber material without deviation from the center axis. CONSTITUTION:The sintered rod 6a is allowed to come down through the reactor 2 vertically and the top of the rod 6a is held with the rotation chuck 1 so that the rod coincide with the rotation center 9 of the chuck 1. Further, the rod 6a is allowed to project from the reactor so that the part below the reactor is longer than about 1/3 of the rod 6a. The porous glass on the rod 6a is softened by heating with the hand burner 7, as the top end of the growing part is allowed to rotate, so that the rotation swing the rod 6a is minimized by pushing the rod with the micrometer 8 and the rotation axis of the rod 6a is almost allowed to coincide with the rotation axis of the chuck 1. In the similar fashion, the bottom end of the growing part 5 is also softened to effect the deposition of glass fine particles on the growing part 5.