Large effective area fiber with graded index ge-free core

Abstract

According to some embodiments an optical waveguide fiber comprises (i) a Ge free core having an effective area of 100 μmto 150 μm, at 1550 nm wavelength, said core comprising: a) a central core region extending radially outwardly from a centerline to a radius r, and having a relative refractive index percent profile Δ(r) in % measured relative to pure silica, wherein −0.1%≦Δ(r)≦0.12%, wherein the central core region has a maximum relative refractive index percent, Δ; (b) a first annular core region surrounding and directly adjacent to the central core region, having an α value 1.5≦α≦10, and extending to an outer radius r, wherein 6 μm≦r≦10 μm, and having a relative refractive index percent profile, Δ(r) in % measured relative to pure silica, a minimum relative refractive index Δ, a maximum relative refractive index Δand the relative refractive index measured at a radius r=2 μm, wherein 0.45≦Δ≦0; −0.25≧Δ≧−0.45 and Δ≧Δ(r=2 μm); (c) a fluorine doped second annular region surrounding and directly adjacent to the first annular core region and extending to a radius 20 μm≦r≦30 μm and having a negative relative refractive index percent profile, Δ(r) in %, measured relative to pure silica, with a minimum relative refractive index percent Δand −0.5%<Δ<−0.25%; and Δ≦Δ; (ii) a cladding surrounding the core and having a relative refractive index percent Δ(r) in % measured relative to pure silica and a minimum refractive index delta Δ, and −0.4%<Δ<−0.2%; wherein the relative refractive index profile of the optical fiber is selected to provide attenuation of no more than 0.17 dB/km at the 1550 nm wavelength.