Experimental investigation on coherent beam combination of a three-element fiber array based on target-in-the-loop technique

A kind of target-in-the-loop (TIL)technique which promises the coherent combination of multi-element laser beams in far field is experimentally demonstrated. The physical model of coherent beam combination (CBC)based on TIL is established. A kind of adaptive fiber optics collimator (AFOC)correcting optical path and tip/tilt errors simultaneously is employed to compensate phase errors between beamlets. The CBC of a 3-element fiber array based on TIL is successfully achieved and a perfect effect of CBC is captured. In this paper, we present a reference for long-distance transmission of multi-element coherent beams in real atmospheric environment.