| 摘要 |
PROBLEM TO BE SOLVED: To establish a process for producing an optical fiber having high strength and a decreased number of times of breakage by setting specific conditions relating to the deviation quantity at the spinning end of an optical fiber preform hung down in a fixing part, such as chuck, and the size of the opening at the bottom end of a heating furnace. SOLUTION: In the process for producing the optical fiber f by inserting the optical fiber preform M into a furnace core tube 4 opened in the vertical direction of the heating furnace 3 and spinning the optical fiber from the bottom end thereof; spinning is executed by setting the relation tanθ<=7.5×10<-3> when the angle of the misalignment formed by the axial line of the optical fiber f extending from the spinning end Ma of the optical fiber preform M hung down in the fixing part 2, such as chuck, to the end of the aperture 3a at the bottom end of the heating furnace 3 and the hanging reference axial line Lc of the optical fiber preform free of the misalignment is defined asθ. Further, the spinning is executed by specifying the ratio (A/B value)) to <=11 when the outside diameter of the hung down optical fiber preform M is defined as A and the bore of the opening 3a at the bottom end of the heating furnace 3 as B. |
