利用描述脉冲激光与体光栅相互作用的耦合波方程，系统研究了不同入射脉宽和啁啾参数的线性啁啾脉冲激光经体光栅衍射时，频域内衍射光谱的振幅和相位变化特性。计算结果表明，衍射啁啾脉冲振幅的光谱宽度受入射脉宽、啁啾参数和体光栅有效衍射谱宽的影响，在体光栅有效衍射谱宽一定时，随着入射脉宽的增大，衍射谱宽减小，衍射效率增大；随着啁啾参数的增大，衍射谱宽增大，衍射效率降低；对于衍射啁啾脉冲频谱的相位分布，随着入射脉宽的增加和啁啾参数的减小，相位变化幅度增大，而且相位分布曲线呈现不对称特性。研究还发现，适当选择体光栅的光栅矢量和入射角，可以利用体光栅的布拉格衍射实现对线性啁啾脉冲激光的整形，而且保持衍射脉冲的频率线性啁啾特性。

Based on the coupled wave equations that describe the interaction of laser pulse with volume gratings, the diffraction properties of volume gratings illuminated by linear chirped pulse with various input pulse widths and chirped parameters are studied. The properties of the spectral intensity and phase of diffraction pulses are investigated. The calculations demonstrate that the diffraction spectral width is influenced by the input pulse width, chirped parameter and the spectral width of the volume grating. With the incident pulse width increasing, the diffraction spectral width is reduced, but the diffraction efficiency increases. With the increase of the chirped parameter, the diffraction spectral width is increased, but the diffraction efficiency decreases. The change of diffraction phase spectra is increased with the increase of the input pulse width and the decrease of the chirped parameter, and the curve of the phase spectral distribution is asymmetric. We also find that the Bragg diffraction of the volume grating can shape the linear chirped pulse laser, and keep perfectly the linear chirp characteristic of the diffraction pulse, when the grating vector and input angle are selected properly.