Patent ID: 8849082

Claim:
An optical fiber comprising: a germania doped central core region having outer radius r 1 and refractive index Δ 1 , a maximum refractive index Δ 1max and an alpha (α) profile where 1≦α≦100; and a cladding region comprising (i) a first inner cladding region having an outer radius r 2 >6 microns and refractive index Δ 2 and 0.3≦r 1 /r 2 ≦0.85; (ii) and a second inner cladding region having an outer radius r 3 >9 microns and comprising refractive index Δ 3 ; and (iii) an outer cladding region surrounding the inner cladding region and comprising refractive index Δ 4 , wherein Δ 1max >Δ 4 , Δ 2 >Δ 3 , Δ 3 <Δ 4 , and 0.01%≦Δ 4 −Δ 3 ≦0.09%, and 0.01%≦Δ 2 −Δ 3 ≦0.2%, the absolute value V 3 of the second inner cladding region is 5%μm 2 ≦V 3 ≦40%μm 2 , said fiber exhibits a 22 m cable cutoff less than or equal to 1260 nm, and has a zero dispersion wavelength, λo, and 1300 nm≦λ 0 ≦1324 nm.