Experimental Demonstration of Efficient Coherent Combining of 19 Fiber Lasers By Adaptive Gain Coefficient SPGD Algorithm

The fiber laser coherent combining system with tiled aperture structure is an effective method to obtain a high-brightness laser. To realize the high-efficiency combining effect, we develop a 19 fiber laser coherent combining system with a filling factor of 0.903. Then the adaptive gain coefficient is added to improve the SPGD algorithm to speed up the convergence. When the phase controller and tilt controller are in closed loop, the power in the bucket (PIB) is as high as 0.48 with the residual phase error σp ∼ λ/21, and the contrast of the far-field intensity pattern is as high as 0.9851, which indicates the system achieving a superior coherent combining effect.