Optical fiber and optical transmission line using the optical fiber

Abstract

An optical fiber for forming an optical transmission line suitable for the wavelength division multiplexing transmission by connecting to a positive dispersion optical fiber is provided. Outside a first glass layer (1), a second glass layer (2), a third glass layer (3) and a fourth glass layer (4) are sequentially disposed. The fourth glass layer (4) is to be a reference layer for a standard of a refractive index. A relative refractive index difference Δ1 of the first glass layer to the reference layer is set 1.6% to 2.6%, inclusive, a relative refractive index difference Δ2 of the second glass layer is set −0.65% to −0.4%, inclusive, and a relative refractive index difference Δ3 of the third glass layer is set 0.15% to 0.5%, inclusive. A relationship among an outer diameter d1 of the first glass layer, an outer diameter d2 of the second glass layer and an outer diameter d3 of the third glass layer is set 2.5≦(d2/d1)≦3.0, and 1.5≦(d3/d2)≦3.0.

Dependencies are inferred from the claim text.