Patent ID: 9423559
Filing Date: 2016-08-23
CPC Classification: G02B,H01S

Claim Text:
1. A multi-core amplification optical fiber comprising: a plurality of core portions doped with a rare-earth element; and a cladding portion positioned at a periphery of the plurality of core portions, the cladding portion having a refractive index lower than a refractive index of the plurality of core portions, wherein a distance between adjacent core portions included in the plurality of core portions is set to such a core-to-core distance that crosstalk of light between cores does not have an effect on the optical characteristics of the adjacent core portions to each other, the number of the core portions included in the plurality of core portions is three or more, and a difference between the core-to-core distances of the at least one set of the adjacent core portions and the core-to-core distances of the other core portions is 0.5 μm to 10 μm.