All-fiber mode adaptive control for high-power LMA fiber laser

In this paper, The works of all-fiber mode adaptive control system for high power LMA fiber laser in our lab were introduced. Mode control experiments with different photonic lanterns were presented. The results of beam quality, output power, efficiency and spectral boarding in the experiments were analyzed. The limitation factor of power scaling and control stability in mode adaptive LMA fiber lasers were discussed. With the optimization of linewidth and control algorithm, The stable control of the LMA gain fiber amplifier with core size of 48 μm has been experimentally demonstrated. At output powers of 1007W, the measured M² factor is 1.97. The experiments validate the adaptive mode control method for LMA high power fiber lasers. Further work was suggested to achieve near single-mode output with higher output power in larger core size of LMA fiber lasers.