Coherent and incoherent combining of fiber array with hexagonal ring distribution

Beam combining of fiber array with hexagonal ring distribution has been studied in detail. The theoretical analysis and numerical calculation results are given to illustrate the propagation properties of the resulting beam through free space. A comparison between the coherent and the incoherent case shows that high peak irradiance and good beam quality for coherent combining can be obtained in the far field. The effects of phase errors and beam quality M2 factor are also studied. Results indicate that the element numbers should be increased to achieve high power and the space between adjacent elements should be reduced to maintain a good beam quality. This is basically the same for both coherent and incoherent beam combining.