According to some embodiments, a multimode optical fiber comprises a graded index glass core with refractive index Δ1, a maximum refractive index delta Δ1MAX, and a core radius between 10 and 40 microns; and cladding region surrounding the core comprising refractive index Δ4, wherein the fiber exhibits an overfilled bandwidth at an operating wavelength in a 900 to 1250 nm wavelength range of greater than 2.5 GHz-km. According to some embodiments the fiber exhibits an overfilled bandwidth at a wavelength between 950 and 1100 nm which is greater than 4 GHz-km. According to some embodiments the fiber exhibits an overfilled bandwidth at a wavelength between 950 and 1100 nm which is greater than 10 GHz-km.