Dispersion compensating optical fiber, and wavelength division multiplexing transmission line using a dispersion compensating optical fiber

摘要

The invention relates to a dispersion compensating optical fiber which is connected to an optical fiber having a positive dispersion value at wavelength band of 1.55 &mgr;m and concurrently has a function of compensating dispersion of optical fibers having a positive dispersion value and a function acting as an optical transmission line, and relates to a wavelength division multiplexing optical transmission line using the dispersion compensating optical fiber. The refractive index profile of the dispersion compensating optical fiber is determined to be W-shaped. 1.0%≦&Dgr;1≦1.4% and −0.45≦&Dgr;2/&Dgr;1≦−0.285 are established where the relative refractive index difference of said center core (1) with respect to said cladding (3) is &Dgr;1 and the relative refractive index difference of said side core (2) with respect to said cladding (3) is &Dgr;2, and further 0.4≦Ra≦0.5 is established where the value Ra (Ra=a/b) of the outer diameter a of the center core (1) with respect to the outer diameter b of the side core (2) is Ra. The dispersion slope at a wavelength of 1.55 &mgr;m is negative, and the dispersion value &sgr; is −50 ps/nm/km≦&sgr;−20 ps/nm/km, wherein the transmission loss is 0.25 dB/km or less, the polarization mode dispersion value is 0.15 ps/km^½ or less, and the mode field diameter is 5.5 &mgr;m or more.