A multicore optical fiber with a reference section having a material defining a marked multicore glass optical fiber. The multicore fibers can be in groupings, for example, the groupings can be in the form of one of an optical fiber ribbon covered by a matrix, and a tight buffered cable. Fiber optic connectors can be assembled to the multicore optical fiber at either or both ends, and the colored portion can be associated with the optical fiber connector aligning the optical core elements with the optical connectors. The assembly can have at least one transceiver device with a transmit port and a receive port defining a two-way communication channel. Further aspects describe methods of manufacturing multicore fibers including application of curable coatings and reference sections.