Multi-core optical fiber, multi-core optical fiber cable, and multi-core optical fiber transmission system

摘要

A multi-core optical fiber according to an embodiment of the present invention is provided with a plurality of core parts, a common cladding, and a coating. Particularly, in order to improve a spectral efficiency per unit sectional area, optical properties typified by the number of core parts, a sectional area of the entire multi-core optical fiber, the sum of power coupling coefficients to a core part n from all the other core parts, and a transmission loss, a non-linear refractive index, an effective area, and a chromatic dispersion of the core part n with the largest crosstalk from other core parts are set so as to satisfy a predetermined relation.

主权项

1. A multi-core optical fiber comprising a plurality of core parts each extending along a predetermined axis, a cladding integrally covering each of the plurality of core parts, and a coating provided on an outer peripheral surface of the cladding,
the multi-core optical fiber satisfying at least one of first to third conditions wherein Acoat represents a cross sectional area of the entire multi-core optical fiber on a cross section orthogonal to the predetermined axis, wherein the first condition is defined in that: each of the core parts enables single-mode transmission at a predetermined wavelength, and wherein αdB,n [dB/km] represents a transmission loss at the predetermined wavelength of a predetermined core part n with the largest crosstalk from other core parts out of the plurality of core parts, n2,n [m2/W] a non-linear refractive index of the predetermined core part n at the predetermined wavelength, Aeff,n [μm2] an effective area of the predetermined core part n at the predetermined wavelength, Dn [ps/(nm·km)] a chromatic dispersion of the predetermined core part n at the predetermined wavelength, ηn [/km] a sum of power coupling coefficients to the predetermined core part n from all the other core parts at the predetermined wavelength, Ncore the number of core parts in the multi-core optical fiber, and Acoat a sectional area of the entire multi-core optical fiber on a cross section perpendicular to the predetermined axis, Expression (1) below is satisfied:NcoreAcoat⁢log2⁢{1+exp⁡(-80⁢ηn)2.10×1010[(108⁢αdB,n-1)3αdB,n⁢108⁢αdB,n⁢Dn⁢(n2,nAeff,n)2log⁡(5.47×103⁢Dn⁢1-10-8⁢αdB,nαdB,n)]13+[1-exp⁡(-80⁢ηn)]}≥7×1.96×102,(1)wherein
the second condition is defined in that: each of the core parts enables single-mode transmission at a predetermined wavelength, and wherein αdB,n [dB/km] represents a transmission loss at the predetermined wavelength of an nth core part out of the plurality of core parts, n2,n [m2/W] a non-linear refractive index of the nth core part at the predetermined wavelength, Aeff,n [μm2] an effective area of the nth core part at the predetermined wavelength, Dn [ps/(nm·km)] a chromatic dispersion of the nth core part at the predetermined wavelength, ηn [/km] a sum of power coupling coefficients to the nth core part from all the other core parts out of the plurality of core parts at the predetermined wavelength, and Acoat a sectional area of the entire multi-core optical fiber on a cross section perpendicular to the predetermined axis, Expression (2) below is satisfied:1Acoat⁢∑n⁢⁢log2⁢{1+exp⁡(-80⁢ηn)2.10×1010[(108⁢αdB,n-1)3αdB,n⁢108⁢αdB,n⁢Dn⁢(n2,nAeff,n)2log⁡(5.47×103⁢Dn⁢1-10-8⁢αdB,nαdB,n)]13+[1-exp⁡(-80⁢ηn)]}≥7×1.96×102,(2)and wherein
the third condition is defined in that: a transmission loss of a spatial mode not guided with the transmission loss of not more than 1 dB/km at a predetermined wavelength, is not less than 0.9 dB/m, and wherein αdB,nm [dB/km] represents a transmission loss at the predetermined wavelength of an mth spatial mode guided with the transmission loss of not more than 1 dB/km at the predetermined wavelength out of spatial modes in an nth core part among the plurality of core parts, n2,nm [m2/W] a non-linear refractive index at the predetermined wavelength of the mth spatial mode in the nth core part, Aeff,nm [μm2] an effective area at the predetermined wavelength of the mth spatial mode in the nth core part, Dnm [ps/(nm·km)] a chromatic dispersion at the predetermined wavelength of the mth spatial mode in the nth core part, ηn [/km] a sum of power coupling coefficients to the nth core part from all the other core parts out of the plurality of core parts, and Acoat a sectional area of the entire multi-core optical fiber on a cross section perpendicular to the predetermined axis, Expression (3) below is satisfied:1Acoat⁢∑n⁢⁢∑m⁢⁢log2⁢{1+exp⁡(-80⁢ηn)2.10×1010[(108⁢αdB,nm-1)3αdB,nm⁢108⁢αdB,nm⁢Dnm⁢(n2,nmAeff,nm)2log⁡(5.47×103⁢Dnm⁢1-10-8⁢αdB,nmαdB,nm)]13+[1-exp⁡(-80⁢ηn)]}≥7×1.96×102.(3)