Coherent beam combination of fiber lasers based on stochastic parallel gradient descent algorithm

Coherent beam combination of fiber laser arrays plays an important role in realizing high power, high radiance fiber laser systems. The stochastic parallel gradient descent (SPGD) algorithm is a newly developed optimization method using the technique of parallel perturbation and stochastic approximation and it is expected that this algorithm can reduce the cost and complexity of a high power fiber laser system when incorporated in its beam combination scheme. In this paper, a numerical simulation model about the fiber laser beam combination system is then established based on beam-quality-metric optimization method. The SPGD algorithm is introduced and used to realize the beam-quality-metric maximization, leading to the maximum output power of the fiber laser system. The results of numerical simulation indicate that the far-field beam intensity optimization method using SPGD algorithm can realize coherent beam combination of fiber laser arrays effectively.