| 摘要 |
PURPOSE:To prevent the neck down shape of a preform of a optical fiber from becoming longer even by raising the spinning linear velocity of the preform of the optical fiber by specifying difference in temperature at a molten part of the tip of the preform of the optical fiber and temperature at a position lower than the part. CONSTITUTION:First, a preform 13 of an optical fiber is inserted into a core tube 3 of a furnace, heated in an inert gas atmosphere such as argon to a high temperature, melted and the preform 13 of the optical fiber is spun in the longer direction of the optical fiber at 100-1,500m/minute to give an optical fiber 15. In obtaining the optical fiber 15 by subjecting the preform 13 of the optical fiber to melt spinning, the temperature at a position E1 of a spinning furnace 1 is 25-50 deg.CX deg.C (X>=0) lower than that at a central part E0. Therefore, the temperature (T1) of the optical fiber 15 positioned located at the position E1 of the spinning furnace 1 is also 25-50 deg.CX deg.C lower than the temperature (T0) at a molten part 13a of the tip of the preform 13 of the optical fiber. By making the temperature, different the neck down shape of the preform 13 of the optical fiber does not become longer than that of a conventional method even if the spinning linear velocity is increased to a high speed of >=300m/minute and the spinning furnace is made compact. |
