Optical fiber

摘要

An optical fiber includes a core section and a cladding section. A k value expressed by k = 4Aeff/(ÀMFD 2 ) is 1.08 or larger, Aeff being an effective area and MFD being a mode field diameter, at a wavelength of 1550 nm, a chromatic dispersion is in a range from +19.0 ps/nm/km to +21.9 ps/nm/km, and MFD is in a range from 10.3 µm to 13.0 µm. The inequality, r 1 < r 2 < r 3 , is established, R = r 3 /r 2 is larger than 1.0 and equal to or smaller than 5.4, and a relative refractive index difference ” 12 of the maximum value N 2 with respect to the minimum value N 1 is 0.05% or higher, r 1 and r 2 being radial positions respectively with minimum and maximum value N 1 and N 2 of a refractive index in the core section and r 3 being a radius of the core section.