| 摘要 |
PROBLEM TO BE SOLVED: To minimize nonlinear effect and bending loss by setting the effective sectional area and bending loss to specified ranges, and setting a cutoff wavelength to a value regularly forming single mode propagation. SOLUTION: A dispersion shifted optical fiber has a wavelength dispersion of substantially zero, in a used wavelength 1.55μm band, an effective sectionab. area Aeff of 70-120μm<2> , a bending loss of 0.17-100dB m, and a cutoff wavelength having a value regularly forming single mode propagation. In order to have such characteristic values, it is necessary to have a refractive index distribution form (profile) in which an annular ring core part 12 having a low refractive index is formed on the outside of a central core part 11 apart from it. In this profile, when the diameter of the central core part 11 is 2a, the inside diameter of the ring core part 12 is 2b, and the width of the ring core part 12 is w, it is required to satisfy b/a>=1.5tie.5 and w/a>=0.5. |
