Fig. 1. Flowchart of the improved algorithm

Fig. 2. Simulation results by GS algorithm，MRAF algorithm and improved algorithm

Fig. 3. Experimental setup

Fig. 4. Experimental results by GS algorithm，MRAF algorithm and improved algorithm

Fig. 5. Iterative optimization curve of three algorithms

Fig. 6. Effect of different beam waist radii on the output spot at the target plane

Fig. 7. Outputs with different deviation of Gaussian beam