| 摘要 |
PROBLEM TO BE SOLVED: To provide a method capable of manufacturing an optical fiber containing an alkali metal element in a core, and having a small transmission loss.SOLUTION: A quartz-based optical fiber preform 20 including a core part containing an alkali metal element having the average concentration of 5 atom ppm or higher and a clad part containing fluorine and CL is drawn by a drawing apparatus 1, to thereby manufacture an optical fiber 30 which comprises a glass part and a resin-coated part, and in which the maximum value of a compression stress remaining in the glass part is 130 MPa or lower. In drawing, a time during which each position of the optical fiber preform is held at a temperature of 1,500°C or higher is preferably 110 minutes or less. |
