光纤激光器频谱组束的理论研究

 建立了由光纤激光器阵列、薄透镜和衍射光栅组成的频谱叠加理论模型，基于高斯光束的变换和衍射理论，推导出远场光强分布的关系式，探讨了系统参量的优化设计并进行了数值模拟。结果表明：当中心波长激光器的-1级干涉主极大与槽面衍射主极大重合、零级干涉主极大刚好落在槽面衍射的+1级零值极小上、其它波长激光器的-1级干涉主极大与中心波长激光器的槽面衍射主极大重合时，输出光束的衍射效率较高；当光栅平面法线与薄透镜光轴的夹角为衍射光栅槽形角的一半时，输出光束的半角宽度较小。

Theoretical study on spectral beam combining of fiber lasers

The theoretical model of spectral beam combining of fiber lasers is presented.It includes a fiber laser array,a lens and a diffraction grating.Based on the conversion and diffraction theories of Gaussian beam,far-field optical intensity expression is derived,and the systemic parameters are optimized.Numerical results show that diffraction efficiency can be improved by overlapping the negative first-order interference principal maximum and the zeroth-order diffraction maximum of the central-wavelength-laser,overlapping the zeroth-order interference principal maximum and the first-order diffraction minima of the central-wavelength-laser,and overlapping the negative first-order interference principal maximums of other lasers and the zeroth-order diffraction maximum of the central-wavelength-laser.The angular width can be reduced by making the grating normal an angle of half blazed angle with the axis of lens.