| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a method for producing an optical fiber whose transmission loss can be reduced without increasing fracture frequency. <P>SOLUTION: In the method for producing an optical fiber using: a wire-drawing furnace 11 performing hot wire-drawing of an optical fiber preform 2; and an annealing furnace 21 arranged at the lower part of the wire-drawing furnace 11 and controlling the virtual temperature of an optical fiber 3 drawn by the wire-drawing furnace 11, the virtual temperature is controlled by passing the optical fiber 3 drawn by the wire-drawing furnace 11 through the inside of the annealing furnace 21 from the upper edge to the lower edge of the annealing furnace 21, and the cleanliness degree of the atmosphere at the lower edge of the annealing furnace 21 is controlled to <500 count/1CF. <P>COPYRIGHT: (C)2010,JPO&INPIT |
