Coherent beam combining of 7 fiber amplifiers based on all-fiber internal phase-locking technique

Abstract

An all-fiber internal phase-locking coherent beam combining (CBC) system is experimental demonstrated. Without the need for any external sampling elements, the relative phase difference signals among the laser channels are detected and compensated before the lasers being emitted into free space. A 7-channel fiber laser array is built to verify the technique experimentally. When the system is in closed loop, the far-field pattern is stable with the fringe contrast of ∼ 95 % and the phase deviation is ∼λ/21. The impacts of phase error, power inconsistency and tilt error to the combining efficiency are analyzed. The all-fiber internal phase-locking system is compact and easy-extending, which could provide a reference for the design of the high-power massive laser array system.