PLASTIC OPTICAL FIBER HIGH IN NUMERICAL APERTURE

PROBLEM TO BE SOLVED: To provide a plastic optical fiber having high numerical aperture of >=0.52 and excellent and well-balanced in heat resistance, flexibility, and environmental resistance. SOLUTION: A plastic optical fiber comprising a clad, a 1st clad and 2nd clad with a composition different from the 1st core, has a configuration of the core consisting of copolymer of methylic methacrylate as a main component, the 1st clad consisting of co-polymer containing fluorinated vinylidene unit and hexafluoropropylene unit, and the 2nd clad consisting of (co-) polymer of fluorinated vinylidene unit as a main component. And, a high numerical aperture optical fiber can be made having high numerical aperture of >=0.52.