In the paper the phase -locked emitters in multicore optical fibers for high power fiber lasers are presented. The simulation of coupling coefficient between cores influences on phase -locking and in the consequence on the far field pattern of the fiber laser based on the analyzed mutlicore optical fiber were performed. In the analyzed fiber laser, while exchanging power of the generated radiation between two adjacent cores on the fiber length (L=5m) within the range of 4% -10%, the radiation becomes phased. Having satisfied this condition, in the far -field low-divergence, high-power laser beam (supermode) is attained.