A high-brightness laser beam from a phase-locked multicore Yb-doped fiber laser array

We observed a high-brightness laser beam emitted from a closely packed array of seven Yb-doped single-mode fiber lasers embedded in a common cladding. The measured slope efficiency, greater than 65%, was achieved by clad-pumping from one end of the fiber. A theoretical model is established to provide a physical interpretation of the measured far field radiation patterns.