| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for manufacturing an optical fiber preform with sufficient manufacturing efficiency which can obtain an optical fiber in which transmission loss characteristics are stabilized. SOLUTION: The method for manufacturing an optical fiber preform includes: a dehydration process in which an optical fiber porous preform 4 is made to drop in a furnace core tube 6 and to pass through a heating region 7, and thereby the optical fiber porous preform 4 is dehydrated; a switching process which pulls up the dehydrated optical fiber porous preform 4 to a prescribed position; and a sintering process in which the optical fiber porous preform 4 which has been pulled up is made to drop again and to pass through the heating region 7 which is made to be at the temperature higher than the heating region temperature in the dehydration process, and thereby the optical fiber porous preform 4 is sintered, wherein when the pulling up speed of the optical fiber porous preform 4 in the switching process is made to be A [mm/minute] and the flow rate of the gas at an ordinary temperature which flows the furnace core tube 6 is made to be B [mm/minute], A≤B is satisfied, and further, 1.5×A≤B is satisfied. COPYRIGHT: (C)2010,JPO&INPIT |
