谱合成是获得高功率激光输出的有效方法。建立相移反射体布拉格光栅谱合成模型，利用传输矩阵法，分析相移反射体布拉格光栅的衍射特性，并对反射体布拉格光栅的衍射特性和相移反射体布拉格光栅的衍射特性进行了比较。以两束光为例，分析相移反射体布拉格光栅谱合成特性，分析在高斯单色平面波入射条件下，光谱宽度对谱合成效率的影响。结果表明，通过在反射体布拉格光栅中引入π/2的相位畸变，可有效抑制衍射效率中的旁瓣的影响并增加参与谱合成的光束数目，对于两束光谱间距为30 pm的窄带光束谱合成，谱合成效率可达97%。

It is an effective approach to obtain high power laser beam output by spectral beam combining. The model of spectral beam combining using phase-shifted reflective volume Bragg gratings is established, and the diffraction characteristic is analyzed by transfer matrix method. The diffraction characteristics of reflective volume Bragg grating and phase-shifted reflective volume Bragg grating are compared. Taking the spectral beam combining of two beams by phased-shifted reflective volume Bragg gratings as an example, the effects of Gaussian monochromatic beam′s spectrum width on combining efficiency are analysed. The results show that the side-lobe of diffraction efficiency can be eliminated and the channel number can be increased by phase-shifted reflective volume Bragg gratings, and the combining efficiency can be more than 97% when the spectral beam combines of two beams with a spectral separation of 30 pm.