| 摘要 |
PURPOSE:To produce an optical fiber preform at the time of drawing a first preform into a second preform rod having a smaller diameter than the former by detecting the tension of the first rod and controlling the power to be supplied to a drawing furnace so that the rod is drawn always with a fixed tension. CONSTITUTION:A first preform rod 1 is passed through a drawing furnace 3 and drawn into a second preform rod 2 having a smaller diameter than the former to produce an optical fiber preform. In this case, a tension detector is provided on the first rod 1 holding means side, and the power to be supplied to the furnace 3 is controlled in accordance with the detected tension of the first rod 1. Consequently, the first rod 1 is drawn with a fixed tension, and the optical fiber is produced. |
