Patent ID: 8837888

Claim:
A multimode optical fiber comprising: a core; and a cladding provided outside the core, wherein in a cross section perpendicular to a central axis of the multimode optical fiber, the core is composed of a central region where a distance from the central axis is not more than 20% of a radius of the core, and a peripheral region surrounding the central region, wherein the core comprises: a region whose refractive-index profile follows an α-power refractive-index profile; and a region where a refractive index has deviation from an ideal shape of the α-power refractive-index profile and where an absolute value of an amount of the deviation is not less than 0.005% in terms of relative refractive-index difference, wherein a point where the absolute value of the amount of the deviation assumes a maximum is in the peripheral region, and wherein a refractive index of the core in the outer side of the point where the absolute value of the amount of the deviation assumes the maximum is lower than a refractive index of the cladding.