摘要 |
An optical transmission line which can restrict both wavelength distortion due to a non-linear phenomenon and wavelength distortion due to dispersion, and which is formed by series-connecting a first optical fiber (8) having a dispersion value of 6 to 14 ps/nm/km in a set wavelength band in a wavelength band of 1.5 mu m and a second optical fiber (9) having a dispersion value of -14 to -6 ps/nm/km in the above set wavelength band, the dispersion slopes of the first optical fiber (8) and the second optical fiber (9) having signs opposite to each other. Light transmitted from an optical transmitter (11) is shone on the first optical fiber, and light transmitted through the first optical fiber (8) is shone on the second optical fiber (9). Absolute value of dispersion in a wavelength band of 1.5 mu m of each optical fiber (8), (9) is set to be at least 6 ps/nm/km to restrict four-light-wave mixing, and the above each absolute value is set to be up to 14 ps/nm/km to restrict local dispersion, to thereby render almost zeroes dispersion values and dispersion slopes in the above set wavelength band over the entire optical transmission line.
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