Tiled-aperture coherent beam combining using optical phase-lock loops

Novel tiled-aperture coherent beam combining architectures using heterodyne optical phase-lock loops (OPLLs) are demonstrated. Two 50 mW off-the-shelf commercial DFB lasers are combined with a Strehl ratio of 0.87. The use of OPLLs for the active phase control eliminates the expensive and bulky optical phase or frequency shifters and enables compact phase-controlled apertures for beam steering.