MULTICORE AMPLIFYING OPTICAL FIBER

摘要

A multi-core amplification optical fiber includes: a plurality of core portions doped with a rare-earth element; an inner cladding portion positioned at a periphery of the plurality of core portions, having a refractive index lower than a refractive index of the plurality of core portions, in which a first hole is formed; and an outer cladding layer positioned at a periphery of the inner cladding portion, having a refractive index lower than the refractive index of the inner cladding portion. Preferably, the first hole is disposed in a region surrounded by the plurality of core portions in a cross-section of the multi-core amplification optical fiber. Thereby, fluctuation of the optical amplification characteristics of the respective core portions is suppressed.