Numerical simulation of the internal active phase-locking coherent beam combining system.

As a promising way to realize high output power while maintaining high beam quality, coherent beam combining (CBC) of fiber lasers has drawn much interest. Phase control is one of the main technologies to fulfill CBC, which is employed to keep the phases of different fiber lasers consistent. Traditional phase control techniques employ beam splitters after the emitting array to obtain phase mismatch information. Different from the traditional phase-locking technique, the internal phase control technique can obtain phase mismatch information before the laser array output to free space, and the technique is compact and easy to expand to a lager array. In this paper, a CBC system based on an internal phase-locking technique is designed, and relative numerical simulations are studied. By using the cascaded technique, the phase control bandwidth can be greatly increased. The simulation results show that hundreds of laser beams can be effectively combined based on the technique. The results of the numerical simulations can provide significant reference for the compact CBC system design and phase control.