Numerical simulation of tilt-tip control in coherent beam combining using SPGD algorithm

作者：Wang Xiong; Wang Xiaolin; Zhou Pu; Xu Xiaojun; Shu Bohong^*

来源：Optics and Laser Technology, 2013, 48: 343-350.

DOI：10.1016/j.optlastec.2012.09.011

• Coherent beam combining
• Fiber laser
• Tilt-tip control

In coherent beam combining of fiber lasers, the combined beam's quality is strongly affected by not only the piston phase differences between each beamlet, but also the tilt-tip errors of each beamlet In this paper, we first presented a numerical model of tilt-tip control, then performed the numerical simulation to investigate the tilt-tip wavefront control in coherent beam combining using stochastic parallel gradient descent (SPGD) algorithm. It is demonstrated that the tilt-tip errors can be compensated effectively using SPGD algorithm. Results show that the increase in both the mean square error (MSE) of tilt-tip errors and the number of lasers degrade the control effect. It is difficult to compensate the tilt-tip errors when the MSE is larger than 75% of each beamlet's divergence angle. When the iteration rate of the SPGD algorithm is 100 Hz, the simulated control bandwidth is 16.50 Hz with tilt-tip errors' MSE of 5% of the divergence angle, and 1.90 Hz with MSE of 8% of the divergence angle.

• 出版日期2013-6
• 单位中国人民解放军国防科学技术大学