光纤激光阵列占空比对相干合成效果影响分析

摘要

根据弗琅和费衍射理论，建立了19路、37路和91路光纤激光相干合成模型，仿真模拟了不同占空比情况下，大阵列合成光束在远场的强度分布和光束质量，分析了占空比排布与合成路数对远场光束质量的影响。仿真结果表明，随着光纤阵列占空比的下降，远场艾里斑内的光强逐渐减小，合成效果变差；反之，远场艾里斑内的光强逐渐增大，合成光束远场能量集中度增强，光束质量变好。因此，提高相干合成的效果，必须提高光束阵列的占空比。%A model of coherent beam combination (CBC) of fiber laser with 19-channel, 37-channel and 91-channel is established according to Fraunhofer diffraction theory. The far-field intensity distribution and beam quality of a large-scale CBC with different duty ratios are simulated. The influences of filling ratio and the number of sub-beams on beam quality of CBC in the far-field are analyzed. Simulation results show that the far field intensity in the Airy spot decreases with the filling ratio of the fiber array decreased, which leads to the degradation of combination effect. On the contrary, the far field intensity in the Airy spot increases with the filling ratio of the fiber array increased and the beam quality of CBC will be better. In order to obtain a high efficiency of CBC, the filling ratio must be improved simultaneously.