倾斜相差对光纤激光相干合成的影响与模拟校正

Influence and simulated correction of tip/tilt phase error on fiber laser coherent beam combination

选取不同路数和不同填充因子的合成光束模型,模拟并分析了倾斜相差对相干合成的影响.介绍了倾斜校正的关键器件——自适应光纤光源准直器.在主振荡功率放大器结构的光纤激光相干合成系统中,模拟了随机并行梯度下降(SPGD)算法校正七路激光阵列间时变倾斜相差的动态过程,分析了不同倾斜相差幅值和频率对校正能力的影响.实验表明,要提高相干合成的效果,必须校正倾斜相差;而SPGD算法校正倾斜相差的能力随着倾斜相差幅值和频率的增加而降低.文章为在实际大气环境中实现多路高功率光纤激光的相干合成提供了参考.

Near-field models of coherent beam combination （CBC） with different beam channels and fill factors are employed,and the influences of tip/tilt phase errors on CBC are studied.The key device for tilt-error correction,named adaptive fiber optics collimator（AFOC）,is introduced.A MOPA-configuration fiber laser CBC system compensating both piston and tip/tilt phase errors is designed.Then,the dynamic courses of tilt-error correction using stochastic parallel gradient descent （SPGD） algorithm in a seven-channel system are simulated,and the effects of CBC at different tilt-error amplitudes and frequencies are investigated.Experimental results show that the tilt-error should be corrected to improve CBC effects,and algorithm＇s control ability drops off when tilt-error amplitude and frequency increase.The results in this paper present a reference for multi-channel high power fiber laser CBC systems in real atmospheric environments.