Abstract: To reduce energy losses which result from the misalignment of cores of connected optical fibers, the energy emanating from the core of a transmitting fiber is expanded over a larger area and then refocused onto the core of a receiving fiber. Several embodiments, based on the optical transmission characteristics of a Luneberg lens, are presented for terminating optical fibers. Since the terminations are substantially larger in size than the core itself, field coupling is greatly facilitated. Further, since the energy has been expanded, a slight misalignment of transmitting and receiving terminations results in a much lower loss than that which would result if the optical fibers were coupled directly with the same amount of core misalignment.