Coherent combining efficiency improvement based on a focused conformal projection fiber laser array

A focused conformal projection system (FCPS) has lots of advantages over parallel projection system, especially in near-field coherent beam combining situation. A home-made FCPS based on fiber laser array with adaptive fiber optics collimator is setup and its performances are investigated. First, the coherent beam combining based on the system is successfully achieved with simultaneous end-cap/tilt control and phase-locking control. Then performances of collimated conformal projection system (CCPS) are examined experimentally and consistent with the theoretical results with efficiencies above 80%. At last, we test the feasibility of FCPS in improving coherent combining efficiency. Results show that comparing with CCPS, the CBC efficiency of FCPS improves about 43.5%, from 59.0% to 84.7%, with perfect fitness to the ideal situation.