PRODUCTION METHOD OF OPTICAL FIBER

摘要

PROBLEM TO BE SOLVED: To enable outer diameter control without being affected by apparent outer diameter fluctuation occurring during drawing.SOLUTION: Projection widths a, b of an optical fiber are measured from two directions orthogonal to the central axis of the drawn optical fiber, and forming mutually an angle φ, and outer diameter control is performed so that a shape feature quantity R showing largeness of a cross section of the optical fiber calculated based on the projection widths a, b and the angle φ measured from the two directions agrees with a prescribed value.SELECTED DRAWING: Figure 4