| 摘要 |
PROBLEM TO BE SOLVED: To obtain a high strength optical fiber by applying a specific treatment to an optical fiber base material to remove fine metal particles adhered and bound to the surface of the base material and causing the surface defects of the optical fiber, when the optical fiber base material is heated and the optical fiber is drawn. SOLUTION: The outer peripheral surface of an optical fiber base material 1 is preliminarily directly heated with a high-frequency induction heater 6 to melt and evaporate fine metal particles (e.g. fine iron particles) adhered or bound to the outer peripheral surface of the optical fiber base material 1. Preferably, the fine metal particles adhered or bound to the outer peripheral surface of the optical fiber base material 1 are thermally melted and evaporated with the high-frequency induction heater 6, and the evaporated fine metal particles are collected in a collector 8. Namely, the high frequency induction heater 6 thermally melt and evaporate the fine metal particles, but does not heat the optical fiber base material itself 1. |
