According to some embodiments an optical
waveguide fiber comprises:(i) a Ge free core having an effective area of 90 μm2 to 160 μm2, at a 1550 nm
wavelength, and α value 12≦α≦25, said core comprising:(a) a central core region extending radially outwardly from a centerline to a
radius 0 μm≦r0≦2 μm, and having a
relative refractive index percent profile Δ0(r) in % measured relative to pure silica, wherein −0.1%≦Δ0(r)≦0.1%, wherein the central core region has a maximum
relative refractive index percent, Δ0MAX,(b) a first annular core region surrounding and directly adjacent to the central core region and extending to an outer
radius r1, wherein 4.8 μm≦r1≦10 μm, and having a
relative refractive index percent profile, Δ1(r) in % measured relative to pure silica, and a minimum relative
refractive index, Δ2MIN, and the relative
refractive index measured at a
radius r=2.5 μm being:−0.15≦Δ1(r=2.5 μm)≦0, and Δ0MAX≧Δ1(r=2.5 μm);(c) a
fluorine doped second annular region surrounding and directly adjacent to the first annular core region and extending to a radius 13 μm≦r2≦30 μm and having a negative relative
refractive index percent profile, Δ2(r) in %, measured relative to pure silica,with a minimum relative refractive index percent Δ2MIN being:Δ2MIN≦Δ1(r=2.5 μm), and −0.7%≦Δ2MIN≦−0.28%;(ii) a cladding surrounding the core and having a relative refractive index percent Δc(r) in % measured relative to pure silica, and Δc(r)=Δ2MIN±0.3%;wherein the relative
refractive index profile of the
optical fiber is selected to provide attenuation of no more than 0.175 dB / km at the
wavelength of 1550 nm.