OPTICAL FIBER, AND DISPERSION COMPENSATOR USING SAME, OPTICAL TRANSMISSION LINE USING SAME AND OPTICAL TRANSMISSION SYSTEM USING SAME

摘要

There is provided an optical fiber for flattening a dispersion slope in a transmission wavelength band and suitable for high bit-rate and high capacity WDM transmission in a wide range. In this optical fiber, conditions of 0.8%.ltoreq..DELTA.1.ltoreq.3.0% , -0.7%.ltoreq..DELTA.2.ltoreq.-0.4%, and 0.2%.ltoreq..DELTA.3.ltoreq.0.5% are satisfied when a relative refractive index difference of the first core with respect to the clad is set to .DELTA.1, a relative refractive index difference of the second core with respect to the clad is set to .DELTA.2, and a relative refractive index difference of the third core with respect to the clad is set to .DELTA.3. A cable cutoff wavelength lies on a short wavelength side from 1520 nm. Further, relations of S < 0 and 0 <(D/S).ltoreq.200 are satisfied in a specific set wavelength band having a range width of not less than 20 nm within a wavelength band of 1.5 .mu.m when a chromatic dispersion at a specific wavelength within the wavelength band of 1.5 .mu.m is set to D (ps/nm/km) and a dispersion slope is set to S (ps/nm2/km).