Optical fiber, optical transmission line and optical communications system

摘要

An optical fiber suitable for use in optical communications systems capable of transmitting and receiving a large volume of information. The optical fiber has a chromatic dispersion of at least 4 ps/nm/km and at most 15 ps/nm/km at a wavelength of 1,550 nm and a transmission loss of at most 0.190 dB/km at a wavelength of 1,530 to 1,570 nm. The optical fiber comprises an inner core (refractive index: n1) including the optical central axis, an outer core (refractive index: n2) encircling the inner core, and a cladding (refractive index: n3) encircling the outer core. The relationship between the refractive indexes is expressed as n1>n2>n3. The inner core is made of practically pure silica glass undoped with GeO2. The outer core and the cladding are doped with a refractive-index-reducing dopant such as fluorine. An optical transmission line and an optical communications system are structured by using the foregoing optical fiber.