Coherent combining of a large-scale fiber laser array over 2.1 km in turbulence based on a beam conformal projection...

We demonstrated a beam conformal projection system for coherent combining of large-scale lasers over 2.1 km in turbulence 20 m above the ground, using the basic modules of a 19-element fiber phased array combined with coarse pointing by a gimbal mount. After coarse pointing and aberration corrections, the metrics (reflected light) of the combined beams from a basic module were best increased by 13.4 times, suggesting that our system promises the great effect of coherent combining under long-distance turbulence. Moreover, we tentatively realized coherent combining of two basic modules (38 lasers), which is the largest number of elements in a fiber laser coherent beam combination outdoors, to the best of our knowledge, with the metrics of combined beams increased by about 29 times.