Experimental research on propagation of incoherent combined beams of fiber lasers in atmospheric turbulence

The paper presents experimental results of the propagation performance of incoherent combined beams of six 100-watt single-mode fiber lasers. The waist size of each laser beam increases from 9 mm to 90 mm when it propagates through the beam expander. The six optical axes of fiber lasers in an array are controlled using individually controlled tip-tilt mirrors. The laser array is propagated to the target at a range of 470 m by a 440-mm beam director in strong and weak atmospheric turbulence. With the decrease in the intensity of turbulence, the ratio of the power in bucket to the total power on the target increases. And the increase ratio due to tip-tilt correction is about 1.7.