Active phase locking of thirty fiber channels using multilevel phase dithering method

作者：Huang, Zhimeng; Tang, Xuan; Luo, Yongquan^*; Liu, Cangli; Li, Jianfeng; Zhang, Dayong; Wang, Xiaojun; Chen, Tunan; Han, Mei

来源：Review of Scientific Instruments, 2016, 87(3): 033109.

DOI：10.1063/1.4943666

• COHERENT BEAM COMBINATION
• AMPLIFIER ARRAY
• ALGORITHM
• FUTURE
• LASERS
• KW

An active phase locking of a large-scale fiber array with thirty channels has been demonstrated experimentally. In the experiment, the first group of thirty phase controllers is used to compensate the phase noises between the elements and the second group of thirty phase modulators is used to impose additional phase disturbances to mimic the phase noises in the high power fiber amplifiers. A multi-level phase dithering algorithm using dual-level rectangular-wave phase modulation and time division multiplexing can achieve the same phase control as single/multi-frequency dithering technique, but without coherent demodulation circuit. The phase locking efficiency of 30 fiber channels is achieved about 98.68%, 97.82%, and 96.50% with no additional phase distortion, modulated phase distortion I (+/- 1 rad), and phase distortion II (+/- 2 rad), corresponding to the phase error of lambda/54, lambda/43, and lambda/34 rms. The contrast of the coherent combined beam profile is about 89%. Experimental results reveal that the multi-level phase dithering technique has great potential in scaling to a large number of laser beams.

• 出版日期2016-3
• 单位北京应用物理与计算数学研究所; 中国工程物理研究院; 中国工程物理研究院激光聚变研究中心; 中国工程物理研究院流体物理研究所