Multi-core optical fiber and multi-core optical fiber cable

A multi-core optical fiber comprising:

• 12 cores each extending along a central axis;
• and
• a common cladding covering each of the 12 cores, wherein
• the common cladding has a circular outer periphery as viewed from a cross-section of the multi-core optical fiber, the cross-section of the multi-core optical fiber being orthogonal to the central axis,
• on the cross-section of the multi-core optical fiber, the 12 cores are arranged such that no adjacent relationship is established between cores each having an adjacent relationship with a specific core selected from the 12 cores, and are respectively arranged such that centers of the 12 cores are line symmetric with respect to a symmetry axis, the symmetry axis intersecting with the central axis and passing through none of the centers of the 12 cores, the adjacent relationship being defined as a relationship between two cores having a center-to-center interval that a difference from a minimum center-to-center interval is 2 μm or less, and
• on the cross-section of the multi-core optical fiber, an arrangement of the centers of the 12 cores has rotational symmetry of one.