针对现有普通偏振分光棱镜（PBS）消光比低、偏振串扰等不足，提出一种由PBS和偏振片构成的高精度偏振分光系统。在PBS的反射通道和透射通道插入偏振片，并调整偏振片的透光轴方向，以便最大程度地抑制偏振串扰。理论计算和数值仿真一致表明，该偏振分光系统能够实现更高精度的偏振分光。实验测得，当入射光强度比为-47.5 dB时，普通PBS的偏振分光误差为57.3%，添加了偏振片的偏振分光系统的偏振分光误差为14.3%；而当入射光强度比为47.8 dB时，普通PBS的偏振分光误差为15.5%, 添加了偏振片的偏振分光系统的偏振分光误差为8.6%。提出的偏振分光系统简单实用，可广泛应用于偏振光学系统中。

The poor extinction ratio and polarization cross talk of a general polarizing beam splitter (PBS) promote us to propose a high-precision polarizing beam splitting system, which consists of a PBS and polarizers. The additional polarizers are insert into reflection channel and transmission channel of the PBS, and the transmission axis direction of polarizer is adjusted, which can minimize the polarization cross talk. Both the theoretical calculation and numerical simulation demonstrate that this polarizing beam splitting system can achieve polarization splitting with higher accuracy. The experimental results show that when the intensity ratio of incident light is -47.5 dB, the polarizing beam splitting error caused by a general PBS is 57.3%, while it is 14.3% after adding polarizer. When the intensity ratio of incident light is 47.8 dB, the polarizing beam splitting error caused by a general PBS is 15.5%, while it is 8.6% after adding polarizer. The proposed polarizing beam splitter system is simple and practical, which can be employed in many polarized optical systems.