Patent ID: 8315495

Claim:
An optical waveguide fiber comprising: (i) a Ge free core having an effective area of 100.4 μm 2 to 160 μm 2 , at a 1550 nm wavelength, and α value 12≦α≦200, said core comprising: (a) a central core region extending radially outwardly from a centerline to a radius ro, and having a relative refractive index percent profile Δ 0 (r) in % measured relative to pure silica, wherein −0.1%≦Δ 0 (r)≦0.1%, wherein the central core region has a maximum relative refractive index percent, Δ 0MAX ; (b) a first annular core region surrounding and directly adjacent to the central core region and extending to an outer radius r 1 , wherein 4.8 μm≦r 1 ≦10 μm, and having a relative refractive index percent profile, Δ 1 (r) in % measured relative to pure silica, and a minimum relative refractive index, Δ 2MIN , and the relative refractive index measured at a radius r=2.5 μm being: −0.15≦Δ 1 ( r =2.5 μm)≦0 and Δ 0MAX ≧Δ 1 ( 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≦r 2 ≦30 μm and having a negative relative refractive index percent profile, Δ 2 (r) in %, measured relative to pure silica, with a minimum relative refractive index percent Δ 2MIN being: Δ 2MIN <Δ 1 ( r =2.5 μm) and −0.5%≦Δ 2MIN ≦−0.27%; (ii) a cladding surrounding the core and having a relative refractive index percent Δ c (r) in % measured relative to pure silica, and Δ c (r)=Δ 2MIN ±0.3%; wherein the relative refractive index profile of the optical fiber is selected to provide attenuation of less than 0.172 dB/km at the 1550 nm wavelength.