| 摘要 |
PURPOSE:To prevent the loss of light of optical fiber due to oxygen defectes in wiredrawing by forming a heating atmosphere of a mixed gas of O2 and F in manufacturing the optical fiber by heating a parent material for the optical fiber at a high temp., and wiredrawing. CONSTITUTION:A parent material 1 for optical fiber is placed in a furnace body 9 having a heating element 6 of zirconia, and the heating element 6 of zirconia is heated by a high-frequency induction coil 8. The parent material 1 for the optical fiber is heated with the high temp., softened, and wiredrawn into an optical fiber 2. In this case, gaseous N2, O2, and CF4 as an inert gas from bombs 3a, 3b, an 3c are mixed in 0.46:0.36:0.18 molar ratio of N2:O2:F, and the mixed gas is introduced into a wiredrawing furnace through a valve 5. The O2 of the parent material glass volatilized by the heating of the parent materal 1 at high temps. is replenished, and the uniform concn. of F in the glass fiber 2 is maintained in this way. In addition, the refractive index distribution of the optical fiber 2 is not changed, an the excellent-quality optical fiber 2 can be obtained. |
