AMPLIFYING OPTICAL FIBER, AND OPTICAL FIBER AMPLIFIER INCLUDING THE SAME

摘要

PROBLEM TO BE SOLVED: To provide an amplifying optical fiber or the like of a structure, which is suitably used to amplify a signal in L band, and which not only has a suppressing effect on normal four light wave mixture generated among signals but also effectively suppresses even the non-degenerate four-wave mixing. SOLUTION: An optical fiber amplifier (1) includes amplifying optical fibers (31 and 32), which each have a core region (311) doped with rare earth elements and has a zero-dispersion wavelength of an excitation light wavelength or less and also has an effective cut-off wavelength not smaller than 1.1μm and not larger than an excitation light wavelength. by using the amplifying optical fibers (31 and 32), not only the normal four light wave mixture but also non- degenerate four-wave mixing can be suppressed effectively.