Abstract: Disclosed is a single-mode optical fiber suitable for and optical transmission line used in WDM (Wavelength Division Multiplexing) system, which has low dispersion slope, sufficient dispersion value and large effective section area over S-, C- and L-band (1460˜1625 nm) to enable high-speed, large-capacity signal transmission. The optical fiber uses the wavelength region from 1460 to 1625 nm, and the optical fiber also has a dispersion value of 0.1˜3.0 ps/nm-km, more preferably 0.3˜2.4 ps/nm-km, at 1460 nm, a dispersion value of 3.0˜5.5 ps/nm-km, more preferably 3.2˜5.2 ps/nm-km, at 1550 nm, and a dispersion value of 4.5˜8.0 ps/nm-km, more preferably 4.8˜7.7 ps/nm-km, at 1625 nm. In addition, the optical fiber has a dispersion slope of 0.023˜0.05 ps/nm-km2 at 1550 nm, an effective sectional area of 35˜50 ?m2 at 1550 nm, an effective section area of 35˜50 ?m2 at 1460 nm.

Abstract: Disclosed is a single-mode optical fiber suitable for and optical transmission line used in WDM (Wavelength Division Multiplexing) system, which has low dispersion slope, sufficient dispersion value and large effective section area over S-, C- and L- band (1460˜1625 nm) to enable high-speed, large-capacity signal transmission. The optical fiber uses the wavelength region from 1460 to 1625 nm, and the optical fiber also has a dispersion value of 0.1˜3.0 ps/nm-km, more preferably 0.3˜2.4 ps/nm-km, at 1460 nm, a dispersion value of 3.0˜5.5 ps/nm-km, more preferably 3.2˜5.2 ps/nm-km, at 1550 nm, and a dispersion value of 4.5˜8.0 ps/nm-km, more preferably 4.8˜7.7 ps/nm-km, at 1625 nm. In addition, the optical fiber has a dispersion slope of 0.023˜0.05 ps/nm-km2 at 1550 nm, an effective sectional area of 35˜50 ?m2 at 1550 nm, an effective section area of 35˜50 ?m2 at 1460 nm.

Abstract: A method for making an optical fiber preform having an ultimately low PMD (Polarization Mode Dispersion) through improvement of ovality is provided. This method has several collapse steps for collapsing an optical fiber preform having a clad/core deposition layer formed in a preform tube in which a rate of collapse is 0.01-0.06 mm/min at each collapsing step. By using this method, ovality and PMD of the optical fiber preform may be improved.