Patent ID: 7031581
Filing Date: 2006-04-18
Classification: G02B,H04B

Abstract:
1. A wavelength division multiplexed transmission path comprising: a dispersion-compensating transmission path comprising a dispersion-shifted fiber, and one type of dispersion-compensating fiber, or two or more types of dispersion-compensating fiber having different chromatic dispersion, wherein the dispersion-shifted fiber comprises: a) a central core segment; a peripheral core segment, provided on the outer periphery of the central core segment; and a clad, provided on the outer periphery of the peripheral core segment, the refractive index profile of the dispersion-shifted fiber is such that the peripheral core segment has a higher refractive index than the central core segment, and the clad has a lower refractive index than the peripheral core segment, the dispersion-shifted fiber has positive chromatic dispersion in a waveband of 1460 nm to 1630 nm, the dispersion-shifted fiber has: c) chromatic dispersion of greater than or equal to +6.0 ps/nm/km and less than or equal to +10 ps/nm/km at a wavelength of 1550 nm; d) a dispersion slope of less than or equal to +0.09 ps/nm the dispersion-compensating fiber comprises: b) a central core segment; an intermediate core segment, provided on the outer periphery of the central core segment; a ring core segment, provided on the outer periphery of the intermediate core segment; and a clad, provided on the outer periphery of the ring core segment, the refractive index profile of the dispersion-compensating fiber is such that the intermediate core segment has a lower refractive index than the central core segment, the ring core segment has a refractive index which is higher than that of the intermediate core segment but lower than that of the central core segment, and the clad has a refractive index which is lower than that of the ring core segment but higher than that of the intermediate core segment, the dispersion-compensating fiber has negative chromatic dispersion in the compensation waveband of the dispersion-compensating fiber, selected from 1460 nm to 1630 nm, the ratio of the radius of the intermediate core segment to the radius of the central core segment is between 2.0 and 3.0, and the ratio of the radius of the ring core segment to the radius of the central core segment is between 3.0 and 5.0, at least one type of dispersion-compensating fiber A comprising the dispersion-compensating transmission path is capable of actual single mode transmission at a wavelength of 1530 nm; and when a dispersion-shifted fiber satisfying the conditions of c) to e) has been compensated, the dispersion compensation rate defined by (Sc the chromatic dispersion of the wavelength division multiplexed transmission path is greater than or equal to −1.0 ps/nm/km and less than or equal to +1.0 ps/nm/km in a used waveband of the wavelength division multiplexed transmission path, which is selected from 1460 nm to 1630 nm.