Coherent beam combining array arrangement with a large number of elements

Abstract

Improving the beam quality is the constant pursuit of the coherent beam combining (CBC), and CBC is developing toward a large number of elements. In this work, we employed the Fermat spiral array (FSA) in CBC and investigated the CBC effects, compared with traditional periodic arrays. With the element number increasing, the filling factor was increased for FSA, while it was decreased for the hexagonal and ring arrays. In particular, the achieved power in the bucket (PIB) of the CBC with FSA was higher than that of the CBC with hexagonal and ring arrays. Furthermore, the CBC with FSA shows the same tolerance to piston phase error as the CBC with the periodic array, according to numerical calculations. These results provide an effective approach to obtaining better CBC effects, as the CBC develops toward a large number of elements.