Optical fiber

摘要

In an optical fiber composed of a core region and a cladding region surrounding the core region and having a plurality of regions made of sub mediums having refractive indices different from a refractive index of a main medium disposed in a main medium constituting this cladding region, these regions made of the sub mediums are arranged in one given or a plurality of a given circular annular regions and the centers of the regions made of the sub mediums in respective circular annular regions are arranged on the same circumference centered at the center of the core.