| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a method producible of an optical fiber in which an alkali metal element is added to a core, and which has a small transmission loss. <P>SOLUTION: A quartz-based optical fiber preform 20 that includes a core part and a cladding part is drawn with a drawing apparatus 1 to form an optical fiber 30, the core part having an alkali metal element with average concentration of ≥5 atomic ppm. During the drawing, the time the temperature of glass is maintained at ≥1,500°C is ≤110 minutes. The drawing speed is preferably ≥1,200 m/min and more preferably 1,500-2,300 m/min. The optical fiber preform 20 preferably has a diameter of 70-170 mmϕ and more preferably 90-150 mmϕ. <P>COPYRIGHT: (C)2013,JPO&INPIT |
