Patent ID: 8478098

Claim:
An optical fiber cable incorporating a multi-core fiber comprising a plurality of cores each extending along a predetermined axis, and a cladding region integrally surrounding the plurality of cores, said optical fiber cable comprising a structure to provide the multi-core fiber with a bend of the smallest value of radii of curvature R th given by the following expression: R th = 1 2 ⁢ β κ 2 ⁢ D nm ⁢ XT S L F where D nm is an intercentral distance between core n and core m in the multi-core fiber, L F a fiber length of the multi-core fiber corresponding to a length between repeater/regenerators in laying the optical fiber cable, β a propagation constant of each core at a first wavelength, κ a coupling coefficient between adjacent cores at the first wavelength, and XT S a maximum value permitted as an average of a distribution of crosstalk after propagation of light of the first wavelength through the fiber length L F .