光纤激光器高阶模式对相干合成特性影响分析

为了分析光纤激光器中高阶模式对相干合成的影响,采用将光纤激光器的基模以及高阶模式近似表示为拉盖尔-高斯光束的线性叠加的方法,利用拉盖尔-高斯光束的传输特性,得到了当光纤激光器的输出光束包含高阶模式时,激光器阵列相干合成的远场光强分布模型。同时以光纤激光器中输出混合模式为LP01和 LP11以及输出混合模式为LP01和LP02两种情况为例,分析了存在高阶模式的远场相干条纹的峰值功率和条纹对比度。结果表明,当光纤激光器中高阶模式为 LP11模时,远场相干条纹的峰值能量随着LP11模的增加线性下降;当光纤激光器中高阶模式为LP02模时,远场相干条纹的条纹对比度随着 LP02模的增加线性下降。

Effect of higher order modes of fiber laser on the characteristics of coherent combination

In order to study the effect of higher order modes of a fiber laser on the characteristics of coherent combination, the fundamental mode and higher order modes in a double-clad fiber laser were approximated to a linear combination of Laguerre-Gauss beams. Based on its propagation law, the far field distribution of fiber laser array was obtained with consideration of higher order modes. The peak intensity and fringe visibility of a fiber laser array mixing with higher modes of LP01 and LP11 and mixing with higher modes of LP01 and LP02 were analyzed respectively. The numerical results show that the peak intensity decreases linearly with LP11 increasing and that the fringe visibility decreases linearly with LP02 increasing.