理论和实验研究了一种基于双多层电介质膜(MLD)光栅色散补偿构型设计的光谱合成激光器，该激光器既实现了多路光纤激光高光束质量共孔径光谱合成输出，也降低了单路光纤激光的线宽要求。优化了该激光器的光束质量退化分析模型，分析了激光波长、光栅色散和光谱结构对光谱合成输出光束质量的影响，实验研究了不同功率水平下的光谱合成输出光束质量变化特性，获得了最大输出功率为9.6 kW的高光束质量共孔径合成输出，光束质量M2为2.9，合成效率达到92.0%。通过进一步压缩每路光纤激光的线宽并提升其功率或增加合成路数，可以获得更高功率和更高光束质量水平的共孔径激光输出。

A spectral beam combination (SBC) laser with dual multi-layer dielectric (MLD) grating dispersion compensation configuration is studied theoretically and experimentally, which can combine multiple-channel fiber lasers into a common aperture beam with high beam quality and reduce the linewidth requirement of the single channel fiber laser. The analysis model of the degradation of beam quality is optimized. The influences of the laser wavelength, the dispersion of grating and the spectral structure on the output beam quality of the SBC laser are analyzed. The variation of the beam quality of the SBC system at different output power levels is also studied experimentally. The output combined beam with the maximum average output power of 9.6 kW is obtained, of which the beam quality factor M2 is 2.9 and the combination efficiency is 92.0%. By reducing the linewidth and improving the output power of each channel fiber laser or increasing the number of channels, the common aperture SBC output beam can be further scaled with higher output power and higher beam quality.