| 摘要 |
When forming a taper portion on an end of a glass base material for manufacturing an optical fiber, the taper portion is formed by fusing the glass base material from a modified point after modifying a center-line displacement amount of a fusing point for a center line of the glass base material to a value not more than a predetermined numeric value. Moreover, in a glass base material for drawing having an effective straight base with an average outside diameter D and a taper portion on one end of the effective straight base, when the glass base material is attached to a drawing apparatus, a ratio ´/D between the average outside diameter D and a taper portion distortion ´ is ´/D<=0.03, and the taper portion distortion ´ is expressed with a maximum value of a center-line displacement amount of the glass base material between an effective straight base end from the taper portion and a distortion evaluating end of the taper portion. In this way, eccentricity of an optical fiber in an early stage of the start of drawing is immediately reduced, and thus the excess length is reduced. |
