A multicore optical fiber that includes seventeen cores arranged in a hexagonally close-packed configuration, each core having a core center and comprising silica and an up-dopant; and a cladding region surrounding the seventeen cores, the cladding region having a cladding edge, an outer diameter, and a cladding composition comprising silica. The outer diameter of the cladding region is between about 100 microns and 150 microns. Further, the hexagonally close-packed configuration has bi-lateral symmetry to accommodate bi-directional data flow within the fiber.