光学参数对非相干光纤激光组束效果的影响

提高非相干光纤激光组束功率，需要尽可能大的光栅衍射效率。通过理论分析和数值仿真，结果表明PTR布拉格光栅存在最佳厚度，并且光栅衍射效率随着光栅频率和组束波长带宽的减小而增大。在光纤阵列宽度一定的条件下，存在最佳光栅频率值使得总体衍射效率取极大值。实际应用中应选取光栅频率200～700mm^-1，组束波长带宽0-20nm，在此基础上进一步设计组束光学系统的其他参数。

Effects of optical parameters on the efficiency of incoherent fiber laser beam combination

In order to increase the output power of incoherent fiber laser beam combination, the diffraction efficiency needs to be improved as much as possible. Through theoretic analysis and numerical simulations, it is proved that the optimum thickness of PTR Bragg grating exists, and its diffraction efficiency increases with the decrease of grating frequency and wavelength bandwidth. In the condition of the constant width of fiber array, the optimum grating frequency is existent, which would make a maximum of total diffraction efficiency. Actually, the grating frequency should be chosen in the range of 200mm-1 to 700mm-1, and the wavelength bandwidth should be chosen in the range of 0nm to 20nm to further design other parameters of fiber laser beam combination system.