高功率光纤激光部分相干合成的可行性及效果分析

提出部分相干合成的概念,论证了谱线宽度和偏振特性并不是影响高功率光纤激光部分相干合成的瓶颈.与完全相干合成的理想情形相比,随着光束线宽的增大,部分相干合成光束的远场光斑图样基本保持不变,但峰值强度和斯特尔(Strehl)比随之减小,光斑能量越来越分散.利用数值计算的方法对部分相干合成与非相干合成光束的远场效果进行了比较分析.计算结果表明,尽管线宽的存在降低了部分相干合成的效果,但与非相干合成相比,部分相干合成的光束仍具有较大优势.

Feasibility Analysis and Effect Evaluation of Partially Coherent Combining of High Power Fiber Lasers

We propose the concept of partially coherent combining and demonstrate that the linewidth and polarization do not confine partially coherent combination of high power fiber lasers. Numerical calculations show when the linewidths of single fiber laser beam get larger, the far-field pattern almost does not change, but the peak power and Strehl value of far-field spot get smaller, which means the degradation of the partially combined beam. Also we compare the far-field effect of partially coherent and incoherent combination, and the numerical results show that partially coherent combined beam has much higher peak intensity and narrower intensity spot than incoherent combined beam. Partially coherent combined beam still overpasses incoherent counterpart although the combined beam is degraded by a relatively large linewidth.