Patent ID: 6694079
Filing Date: 2004-02-17
Classification: G02B

Abstract:
A dispersion-shifted optical fiber hang a refractive index distribution shape, comprising a center core portion of high refractive index, a step core portion of lower refractive index than said center core portion, provided about outer circumference thereof; and clad of lower refractive index than said step core portion, provided about outer circumference of the step core portion;wherein the dispersion-shifted optical fiber has, in a used wavelength band selected from 1490 to 1625 nm, Aeff of 45 to 90 &mgr;m2, dispersion slope of from 0.05 to 0.14 ps/km/nm2, bending loss of 100 dB/m or less, and chromatic dispersion value of either from âˆ’0.5 to âˆ’8.0 ps/km/nm or from +0.05 to +10.0 ps/km/nm, and has a cutoff wavelength such that substantially single-mode propagation is realized; wherein larger diameter solution is adopted for core diameter, and said dispersion-shifted optical fiber has, in a used wavelength band selected from 1490 to 1625 nm, Aeff of 45 to 70 &mgr;m2, dispersion slope of from 0.05 to 0.08 ps/km/nm2, bending loss of 100 dB/m or less, and chromatic dispersion value of from âˆ’0.5 to âˆ’8.0 ps/km/nm, and has a cutoff wavelength such that substantially single-mode propagation is realized; and wherein when radius of said center core portion is represented as r1, radius of said step core portion as r2, relative refractive-index difference of said center core portion when refractive index of outermost clad is taken as reference as &Dgr;1, and relative refractive-index difference of said step core portion as &Dgr;2, r2/r1 is from 4 to 12, &Dgr;2/&Dgr;1 is from 0.05 to 0.15, and &Dgr;1 is from 0.55 to 0.85%.