色散控制是超快光学中非常重要的环节。介绍了一种利用棱镜、光栅组合而成的反射型棱栅，采用光线追迹法，分析其各阶色散，同时讨论了棱镜和光栅间距、光栅常数等结构参数对色散的影响。结果表明，棱栅的二阶色散随棱镜与光栅间距的增大而增加，而三阶色散减小。同时，前后两个棱镜和光栅间距可以不对称，以便调节棱栅色散值。随着入射角的增加，二阶色散减小，三阶色散增加。当光栅常数变化时，棱栅的色散变化很明显。棱栅间距对棱栅色散影响很小。在工程中设计棱栅时，可通过调节棱镜与光栅间距、入射角、光栅常数等结构参数改变棱栅的色散量，满足超快光学系统的需求。

Dispersion controllment is an important step in ultrafast optics. A reflection grism is introduced, which is composed of the prism and grating. The dispersion of the grism is analyzed with ray-tracing method, and the impact of grism structural parameters on the dispersion is discussed. As seen from the results, the second-order dispersion increases with the separation of the prism and grating, however, the third-order dispersion decreases. The separation of two grisms can be asymmetric in order to adjust the dispersion value of grism pair. The second-order dispersion of grism decreases with the incidence angle, and the third-order dispersion increases with the angle. When the grating constant is changed, grism dispersion corresponding changes. The separation of the grism-pair has little effect on the dispersion of grism. The results show that the dispersion of grism is heavily influenced by the separation of the prism and grating, incidence angle, and the grating constant. By adjusting the above parameters to change the dispersion of grism, it can meet the needs of ultrafast optics.