Tiled-aperture coherent beam combining of two high-power fibre amplifiers

• Published in: Chinese physics B Vol. 19; no. 1; pp. 289 - 293
• Main Author: 周朴 马阎星 王小林 马浩统 许晓军 刘泽金
• Format: Journal Article
• Language: English
• Published: IOP Publishing 2010
• Subjects: Active control; Amplifiers; Beams (radiation); Coherence; Computation; Digital; Fibre; Laser beams; Phase control; 光纤放大器; 数字锁相放大器; 相干光束; 空间反射镜; 输出功率; 闭环性能; 高功率
• ISSN: 1674-1056; 2058-3834
• DOI: 10.1088/1674-1056/19/1/014202

We demonstrate coherent beam combining of two tiled-aperture single-frequency fibre amplifiers with a total output power of 29.65 W by using the multi-dithering technique. The two laser beams are packaged closely by using free-space mirrors side by side into a tiled-aperture with a near-field fill factor of 62%. Active phase control of the amplifier is performed on commercially available digital lock-in amplifiers. Experimental results show that the power contained in the main-lobe in closed-loop is 1.72 times greater than that in open-loop, which is 86% for the ideal case. The fringe contrast of the far-field fringe pattern is as high as 80% when the system is in closed-loop. The beam quality of the combined beam is computed to he BQ = 1.48. The whole system in closed-loop performs well in a long-time observation.