“…In contrast, multicore fibers Photonics 2021, 8, 314 2 of 13 with sufficiently coupled cores [21] support the propagation of the supermodes in which the coherency between the light in the cores can be maintained without the need for any feedback system. Moreover, the MCFs with coupled cores are attractive for exploration of many nonlinear and laser phenomena, including selective mode amplification [22], Raman lasing [23,24], spatiotemporal pulse compression [25,26], light bullet and soliton formation [27][28][29], supercontinuum generation [30], radiation trapping, and pulse cleaning [31,32]. Recent studies have shown that in the MCFs with coupled cores there are regimes of light propagation that are stable at high power and maintain coherency between the channels [33][34][35][36].…”