| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical fiber drawing furnace and a drawing method that are configured such that the temperature difference between an optical fiber glass preform and a cap member enclosing a tapered part of the glass preform is increased to suppress variations in in-furnace temperature and in-furnace pressure, thereby reducing changes in outer diameter of an optical fiber.SOLUTION: An optical fiber drawing furnace is configured to draw an optical fiber 12 by heating a glass preform 11, in which a dummy rod 13 having a diameter different from that of the glass preform is connected to the upper part, by a heating furnace. The optical fiber drawing furnace includes: a first seal part 20 that seals the clearance between the outer peripheral surface of the glass preform 11 and an insertion port 15a at the upper end of the heating furnace; and a cap member 21 that encloses a tapered part 11a at the upper part of the glass preform, seals the first seal part from above when the tapered part passes through the insertion port, and has a second seal part 22 which is provided at its upper part and seals the clearance in-between the outer peripheral surface of the dummy rod 13. The cap member 21 is formed of quartz glass that transmits radiation light from the heating furnace and the glass preform. |
