Active coherent beam combining and beam steering using a spatial mode multiplexer

Coherent beam combination is one promising way to overcome the power limit of one single laser. In this paper, we use a Multi-Plane Light Converter to combine 12 fibers at 1.03 micron with a phase locking setup. The overall loss measurement gives a combination efficiency in the fundamental Hermite-Gaussian mode as high as 70%. This setup can generate the fundamental and higher-order Hermite-Gaussian modes and has beam steering capabilities.