| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical fiber capable of suppressing the signal light distortion occurring in a wavelength dispersion characteristic and the signal light distortion occurring in a nonlinear phenomenon. SOLUTION: The refractive index distribution structure in which the relation among the refractive index n1 of a center core 3, the refractive index n2 of a side core 4 around the same, the refractive index n3 of a segment core 6 around the same and the refractive index n0 of the clad layer 5 around the same is set at n1>n3>n0>n2 is adopted. The difference (Δ1-Δ2) between the specific refractive index difference Δ1 of the center core 3 from the clad layer 5 and the specific refractive index difference Δ2 of the side core 4 from the clad layer 5 is confined to <=0.7%, Δto <=0.6% and specific refractive index difference Δ3 with the clad layer 5 of the segment core 6 is <=0.3% and the mode field diameter at a wavelength 1550 nm is specified to about >=8.6 μm, by which low linearity is attained. In addition, the absolute value of a weight average dispersion slope from a wavelength 1530 nm to 1570 nm is confined to about <=0.04 ps/nm<2> /km, by which the dispersion slope is flattened. |
