An optical fiber is provided. The optical fiber includes a core located at the center of the optical fiber and having a maximum refractive index in the optical fiber, and a cladding located at a circumference of the core and having a refractive index lower than that of the core. The core has a structure in which sub-core areas having the refractive index higher than those of adjacent sub-core areas and sub-core areas having the refractive index lower than those of adjacent sub-core areas are alternately repeated.