Optical transmission line, negative dispersion optical fiber used for the optical transmission line, and optical transmission system comprising optical transmission line

An optical transmission line comprising:

• a positive dispersion optical fiber having a positive dispersion and a positive dispersion slope in a p redetermined wavelength band within a wavelength band of 1570 to 1620 nm (L-band);
• a negative dispersion optical fiber having a negative dispersion and a negative dispersion slope in a predetermined wavelength band adjacent to the L-band, and having a transmission loss of 0.27 dB/km or less in the wavelength band adjacent to the L-band, a polarization mode dispersion of 0.15 ps/km½ or less, a mode field diameter of 5.5 μm or more, and a bending loss that enables the negative dispersion optical fiber to be formed as a cable suitable for use as part of said transmission line;
• and
• a fiber for dispersion characteristics adjustment to compensate the dispersion and the dispersion slope in said predetermined wavelength band of said optical transmission line comprising said positive dispersion optical fiber and said negative dispersion optical fiber, wherein the dispersion value in said predetermined wavelength band falls within a range of −1 to 1 ps/nm/km in the entire optical transmission line comprising said positive dispersion optical fiber, said negative dispersion optical fiber and said fiber for dispersion characteristics adjustment.

An optical transmission line comprising:

• a positive dispersion optical fiber having a positive dispersion and a positive dispersion slope in a predetermined wavelength band within a wavelength band of 1520 to 1570 nm (C-band);
• a negative dispersion optical fiber having a negative dispersion and a negative dispersion slope in a predetermined wavelength band adjacent to the C-band, and having a transmission loss of 0.27 dB/km or less in the wavelength band adjacent to the C-band, a polarization mode dispersion of 0.15 ps/km½ or less, a mode field diameter of 5.5 μm or more, and a bending loss that enables the negative dispersion optical fiber to be formed as a cable suitable for use as part of said transmission line;
• and
• a fiber for dispersion characteristics adjustment to compensate the dispersion and the dispersion slope in said predetermined wavelength band of an optical transmission line comprising said positive dispersion optical fiber and said negative dispersion optical fiber, wherein the dispersion value in said predetermined wavelength band within said C-band falls within a range of −1 to 1 ps/nm/km in the entire optical transmission line comprising said positive dispersion optical fiber said negative dispersion optical fiber and said fiber for dispersion characteristics adjustment.