| 摘要 |
<P>PROBLEM TO BE SOLVED: To achieve stable drawing from a center part by suppressing partial decrease of an optical fiber preform, by facilitating position adjustment of the optical fiber preform in a furnace core tube. <P>SOLUTION: A drawing furnace 10 includes a heating furnace 1 having a furnace core tube 2 for heating and melting an optical fiber preform 20, and a lower extension tube 5 for protecting from the outside air, an optical fiber obtained by drawing the optical fiber preform 20 under the heating furnace 1. At least a part of the lower extension tube 5 is moved downward with respect to the heating furnace 1. In the state where the lower extension tube 5 is moved downward, position adjustment of the optical fiber preform 20 can be performed, while observing the inside of the furnace core tube 2, by utilizing a space between the lower extension tube 5 and the heating furnace 1. <P>COPYRIGHT: (C)2013,JPO&INPIT |
