  There exists the phase ambiguity problem in the coherent beam combining (CBC)
system with centrosymmetric arrays, which means that multiple different piston
aberrations may generate the same far-field image. This will cause that the
far-field image can not correctly reflect the phase information, resulting in
the performance degradation of image-based intelligent algorithms. In this
paper, we make a theoretical analysis on phase ambiguity. To the best of our
knowledge, we give the number and descriptions of all solutions of the phase
ambiguity problem in above system for the first time. A method to solve phase
ambiguity is proposed, which requires no additional optical devices. We
designed simulations to verify our conclusions and methods. We believe that our
work solves the phase ambiguity problem in theory and is conducive to improving
the performance of image-based algorithms. In addition, we designed a two-stage
algorithm to generate Bi-beam, which have valuables application in laser
propagation.
