| 摘要 |
PROBLEM TO BE SOLVED: To provide a fiber for an optical fiber amplifier having gain characteristics without wavelength dependence in wavelength multiplex transmission. SOLUTION: The fiber has a structure composed of a bundle of a plurality of first cores 1 consisting of synthetic quartz with addition of rare earth elements and at least aluminum and second cores 2 consisting of synthetic quartz with addition of rare earth elements and at least phosphorus, and of a clad layer 6 surrounding the cores. The cores are arranged to compensate the absorption characteristics of the first cores 1 and the absorption characteristics of the second cores 2 with each other. |
