基于偏振自适应和主动相位控制的相干合成的实验研究

摘要

An experiment of coherent beam combination of a polarization maintaining(PM) ytterbium doped fiber amplifier (YDFA) and a non-PM YDFA is carried out. The adaptive polarization control based on the stochastic parallel gradient descent (SPGD) algorithm is obtained in the non-PM YDFA to make the output light polarization stable. The single frequency dithering algorithm is taken to compensate the phase errors in the system. The contrast of the far-field pattern increases remarkably from 80. 1% to 87. 2%. A scalable architecture for coherent beam combining of two styles of fiber amplifiers is also proposed.%进行了非保偏放大器与保偏放大器的相干合成的实验研究.通过随机并行梯度下降(SPGD)算法对非保偏放大器进行偏振自适应控制,使非保偏放大器输出激光的消光比达到11.5 dB,与保偏放大器在同一偏振方向上的光功率占总功率的93.4％.利用单抖动法进行非保偏放大器与保偏放大器的主动相位控制,实现相干合成.实验结果表明:SPGD算法能够有效实现偏振自适应控制,偏振自适应控制前后相干合成远场的条纹对比度从80.1％提高到87.2％,相干合成的效果提升明显;通过增加参与合成的放大器路数,并在各路激光中引入多级功率放大器,能够得到更高的合成功率输出.