| 摘要 |
PURPOSE:To decrease the remaining undrawn quantity after drawing at the time when a large-diameter optical fiber base material is used by providing 1st and 2nd heat zones to a drawing furnace and drawing the optical fiber base material to a small diameter in the 1st heat zone, then drawing the base material to an optical fiber in the 2nd heat zone. CONSTITUTION:The 1st heat zone A having a 1st heater 11 and the 2nd heat zone B having a 2nd heater 12 are provided to the drawing furnace 10. The large-diameter optical fiber base material 2 mounted to a dummy bar 1 is supplied at a specified speed by a feeder 3 to the drawing furnace 10. The base material is then stretched while the material is heated and softened in the 1st heat zone A by which the small-diameter optical fiber base material is produced. The base material drawn to the small diameter is then introduced into the 2nd heat zone B, where the base material is drawn under heating and softening to produce the optical fiber 4. The undrawn part remaining after the drawing is thereby made into the optical fiber base material drawn to the small diameter and the remaining undrawn quantity is decreased. |
