| 摘要 |
PURPOSE:To manufacture a nearly colorless fiber contg. P in the core and having a low OH content by spinning a fiber and heating it immediately after primary coating. CONSTITUTION:A base material 10 for an optical fiber having a core contg. P is heated in a heating furnace 12 for spinning to spin a fiber, and the fiber is subjected to primary coating with an extruder 16 for primary coating. Immediately after the coating, the fiber is heated at 350-500 deg.C for 2-10sec in a heating furnace 18 for heat treatment, and it is coiled around a coiling drum 20. In case of a conventional fiber having a core of P doped quartz glass, a large absorption loss in the range of ultraviolet rays-visible light-near infrared rays is caused in the fiber immediately after spinning, and coloration is also caused. A P doped fiber having a low OH content and causing a small loss even in the visible region can be obtd. by carrying out said heat treatment. |
