AMPLIFYING OPTICAL FIBER AND OPTICAL AMPLIFIER

摘要

A plurality of cores 51 is disposed around the center axis of a first cladding 52 in a state in which an inter-core distance Λ of cores adjacent to each other is equal, a refractive index n1 of the core 51 is provided higher than a refractive index n2 of the first cladding 52, and the refractive index n2 of the first cladding 52 is provided higher than a refractive index n3 of a second cladding 53. Moreover, 5.8≦Λ/MFD(2λc/(λc+λop))≦8 is satisfied, where the inter-core distance is defined as Λ, a mode field diameter of the core is defined as MFD, a cutoff wavelength is defined as λc, and a wavelength of communication light incident on the core 51 is defined as λop.

主权项

1. An amplifying optical fiber comprising:
a plurality of cores to which an active element is doped; a first cladding enclosing the plurality of cores with no gap; and a second cladding enclosing the first cladding, wherein: the plurality of cores is disposed around a center axis of the first cladding in a state in which an inter-core distance between cores adjacent to each other is equal; a refractive index of the core is provided higher than a refractive index of the first cladding; the refractive index of the first cladding is provided higher than a refractive index of the second cladding; and an expression below is satisfied:
5.8≦Λ/MFD(2λc/(λc+λop))≦8 where the inter-core distance is defined as Λ, a mode field diameter of the core is defined as MFD, a cutoff wavelength is defined as λc, and a wavelength of communication light incident on the core is defined as λop.