Patent ID: 8837890

Claim:
A multimode optical fiber comprising: a graded index glass core having a diameter in the range of 41 microns to 80 microns, a graded index having an alpha profile wherein 1.9≦α≦2.04 and a maximum relative refractive index Δ 1MAX in the range 0.6%<Δ 1MAX <1.6%, and the numerical aperture of the core is the range 0.17≦NA≦0.23; and a cladding surrounding and in contact with the core, said cladding comprising an inner annular portion surrounding and in contact with the core with relative refractive index delta Δ 2 , measured at the outer radius R 2 and R2 is the smallest radius where the first derivative d(Δ/Δ 1MAX )/d(r/R 1 ), is equal to −2.5; and a depressed-index annular portion surrounding the inner annular portion, wherein the fiber has an overfilled bandwidth greater than 2500 MHz-km at 1310 nm.