高功率平顶光束在激光加工领域具有广泛的应用。针对光束平顶化的问题, 提出利用大芯径多模光纤对高斯光束整形的方法。采用RP Fiber Power建立高斯光束传输模型, 仿真分析光纤内光束的传输及强度分布特性。研究结果表明, 多模光纤对高斯光束具有整形作用。高斯光束经多模光纤传输后, 传导模数量增加, 能量由中心向径向移动, 光束质量下降, 能量分布趋于均匀化。光纤的芯径越大, 传输长度越长, 匀化效果越明显。采用D型纤芯结构, 或凹面折射率分布光纤, 均可快速匀化光束。

High Power and flat-topped laser radiation has many widely uses in laser industrial application. Gaussian beam can be converted to flat-topped beam by utilizing larger core multimode fiber. Laser beam transmission model was created up with RP Fiber Power soft. The results show that the multimode fibers have the function of beam shaping. After transmitting of single mode Gaussian beam laser, the number of guide modes increases, and the energy transfers from central to edge. The beam quality decreases and the intensity distribution becomes more homogeneous. The larger radius and length of fiber lead to better homogeneous effect. Both D-shaped multimode fiber and fiber with central-dip profile index can be used to improved the uniformity of transmitting beam.