| abstract |
(57) [PROBLEMS] To provide a multi-core optical fiber, an optical fiber cable, and an optical fiber cable with a plug, which have a small bending loss and transmission loss, and have a wide band. SOLUTION: A sea-island structure in which a plurality of types of island portions having different diameters are integrated by a sea portion in a state of being separated from each other, so that an outer-diameter island diameter is smaller than a center-side island diameter. A plastic mixed multi-core optical fiber in which island portions are disposed, an optical fiber cable having a coating layer formed on an outer peripheral portion of the optical fiber, and a plug portion disposed at at least one end of the optical fiber cable; An optical fiber cable with a plug, characterized in that: |