Patent ID: 7603015

Claim:
An optical fiber comprising: a glass core extending from a centerline to a radius R 1, wherein R 1 <5 μm; a glass cladding surrounding and in contact with the core, the cladding comprising: a first annular region extending from a radius R 1 to a radius R 2, the first annular region comprising a radial width, W 2 =R 2 −R 1 , a second annular region extending from the radius R 2 to a radius R 3 , and comprising a radial width, W 3 =R 3 −R 2 , and a third annular region surrounding the second annular region and extending from the radius R 3 to an outermost glass radius R 4; wherein the core comprises a maximum relative refractive index, Δ 1MAX , relative to the third annular region; wherein said first annular region comprises index delta Δ 2 (r) relative to the third annular region; the second annular region comprises: a minimum relative refractive index, Δ 3MIN , relative to the third annular region; wherein Δ 1MAX >Δ 2MAX >Δ 3MIN , and Δ 2MIN >Δ 3MIN and Δ 3MIN <−0.025; and wherein the core and the cladding provide a fiber with cable cutoff less than 1500 nm, dispersion at 1550 nm less than 12 ps/nm/km, and an effective area at 1550 nm greater than 80.3 μm 2 .