Fig. 1. Schematic diagram of MMF laser amplifier based on wavefront shaping

Fig. 2. Light intensity distribution at the MMF output facet, where white circles are the boundary of fiber core, and blue circles indicate the target area. (a) Relative size of core and target area; (b) (c) beam profile before WFS; (d) beam profile after WFS

Fig. 3. Optimization process and result of GA. (a) Variation of objective function during the optimization process; (b) optimized phase map on SLM