| 摘要 |
PURPOSE:To reduce the variance in the diameter of an optical fiber by uniformly blowing an inert gas on the periphery of the optical fiber along the axis of the furnace core tube of a heating furnace and in parallel with the axis in the title method for drawing the optical fiber while introducing the inert gas into the heating furnace. CONSTITUTION:The optical fiber base material is inserted along the axis of the furnace core tube 6 surrounded with an annular heater 7, the tip end part is heated by the high temp. of the furnace core tube 6 to form a contracted part 2, and the base material is drawn into an optical fiber 3 having a specified outer diameter. In this case, plural concentric cylindrical blow off ports 41-43 coaxial with the furnace core tube 6 are provided on the upper end of the furnace core tube 6, and inert gases g1-g3 are blown off from the respective ports into the furnace core tube 6 along the gap between the furnace core tube 6 and the optical fiber base material. |
