| 摘要 |
PROBLEM TO BE SOLVED: To provide a production method for a single mode optical fiber which prevents an occurance of a residual kink or a fine defect, while reducing torsion numbers to obtain a predetermined PMD value in a high speed delineating. SOLUTION: The single mode optical fiber has a core and a clad and a core-clad specific refractive index difference is 0.3-0.5%, when the single mode optical fiber whose mode field diameter is 8-10μm in a wave length of 1,310 nm is wire-drawn at a speed of 500 m per minute or more, a twist which repeats a clockwise rotation and an anti-clockwise rotation is given. A clad noncircular ratio of an optical fiber is set to x (unit: %) and the number of twist rotations per 1 m is set to y. A maximum of the number of twist rotations is set so that exp (24x-12)<=y<=4 is satisfied, and a PMD in the wave length is made to 0.5 Ps.km<-1/2> or less. |
