Multi-core fiber optic amplifier, multi-core fiber optic amplifier and optical communication system

摘要

PROBLEM TO BE SOLVED: To provide a multi-core optical amplification fiber having suitable characteristics, and a multi-core optical fiber amplifier and an optical communication system using the same. SOLUTION: A multi-core optical amplification fiber is an inner clad located on the outer periphery of each of a plurality of core portions to which a rare earth element is added and the plurality of core portions, and has a refractive index lower than the maximum refractive index of each core portion. The outer clad portion is located on the outer periphery of the inner clad portion and has a refractive index lower than the refractive index of the inner clad portion, and the cutoff wavelength is a wavelength equal to or lower than the photoamplification wavelength band of the rare earth element. The core portion is designed so as to be such that, in the optical amplification wavelength band, the leakage loss of the core portion closest to the outer edge of the inner clad portion among the plurality of core portions is 0.1 dB / 100 m or less. Has a clad thickness. [Selection diagram] Fig. 1