Research progress of fiber laser coherent combining

In recent years, the coherent beam combining technique for laser transmission in atmosphere has been widely investigated, while the study of this technique's application in space optical communications is few. In fact, the structure of multi-aperture receiving antenna based on coherent beam combining could be employed to correct the atmospheric turbulence effect and to enhance the performance of the space optical communication system. In the paper, the recent development of coherent beam transmission and control technique for laser transmission application in atmosphere is reviewed. Then, the research progress of fiber-based coherent beam combining in multi-aperture receiving space optical communication system is reported in detail, including the coherent combining based on 3-dB fiber coupler and the coherent polarization combining based on fiber polarization beam combiner, which might have great potential in space optical communication system.