Coherent propagation and amplification of intense wave beams in a deformed multicore fiber

The transformation of the out-of-phase distribution of the wave field at a structural deformation of a multicore fiber (MCF), including fiber bending and gain inhomogeneity in different cores, is studied. A nonlinear supermode is found, which is weakly sensitive to deformations of the MCF in the case of high-power radiation. It is shown that nonuniformity of the wave field amplitude in different cores decreases with an increase in the total radiation power. In particular, amplification of the wave beam in the form of the found out-of-phase solution in an active MCF leads to equalization of the wave field amplitudes in all cores at a power exceeding the found critical value even in a strongly deformed MCF. Additionally, approximate expressions of spatiotemporal solitons were found in such MCF, the existence and stability of which is confirmed by direct numerical simulation.