Real-time aberration correction simulation of multimode beam by SPGD algorithm

Abstract

In this paper, the physical properties of multimode beam are analysed by using the theory of partially coherent light. Based on the spatial coherence measurement results of a multimode fiber laser, we provide a theoretical basis for aberration correction for multimode beams. To improve the beam quality of multimode lasers, phase correction of multimode laser based on a dual-phase-only liquid-crystal spatial light modulator is presented which is used as aberration correction device. The phase distribution was optimized by the stochastic parallel gradient descent algorithm. In this paper the power in the bucket of the far field was used as the evaluation function and the multimode beam included multiple higher order Laguerre-Gaussian beam modes. The real-time aberration correction of Multimode beam by stochastic parallel gradient descent Algorithm is simulated studied and experimental analysed respectively. According to the results the parameters of stochastic parallel gradient descent algorithm can be adjusted and the efficiency and practicability of the algorithm are determined.