为了扩展光学相控阵的角度扫描范围，设计了基于体全息光栅的放大级，研究了光栅结构参数及其制作误差对性能的影响规律，提出了容差优化方法。研究结果表明：光栅厚度和折射率调制度是影响衍射效率的主要参数，光栅周期和光栅厚度是影响角度选择性的主要参数。光栅出入射角由光栅周期和光栅矢量倾斜角决定，在保持角放大率不变时，可以通过在出入射面内旋转介质调节这两个参数。实际制作中，光栅周期误差和光栅矢量倾斜角误差会导致衍射角偏离设计值，读出光波长越长，光栅周期误差的影响越小；光栅后面介质折射率越高，光栅矢量倾斜角误差影响越小。增加光栅厚度设计值可以减小光栅厚度误差对衍射效率的影响，而减小光栅厚度设计值可以减小折射率调制度误差对衍射效率的影响，实际制备时，需结合系统需求进行综合设计。

To enlarge the steering range of optical phased array, volume holographic grating is employed to act as amplifier stage. The influence of structure parameters and fabrication errors on the performance of grating is studied, and tolerance optimization is proposed to reduce the influence. The results show that grating thickness and refractive index modulation are main parameters that affect diffraction efficiency; grating period and thickness are main parameters that affect angular selectivity. Bragg angle and diffraction angle are determined by grating period and grating vector slant angle, which can be adjusted by rotating medium in the incident and diffraction plane if the angular magnification keeps unchanged. In fabrication process, grating period error and grating vector slant angle error will make diffraction angle diverging design value. The longer readout beam wavelength is, the less impact grating period error has; the higher medium refractive index behind grating is, the less impact grating vector slant angle error has. Increasing grating thickness design value can reduce the impact of grating thickness error on diffraction efficiency, while reducing grating thickness design value can reduce the impact of refractive index modulation error on diffraction efficiency, so it′s necessary to combine with the optical phased array system′s requirements to make integrated design.