主要研究了保偏光纤与Y型波导输入端的对准耦合。基于模场重叠积分法，数值计算5个自由度上的对准偏差对耦合损耗的影响，并设计了一种基于数字图像的实验方案。仿真与实验结果吻合较好,证明该实验方案可行。结果表明：横向位错X和Y对耦合损耗的影响最大，纵向间距Z对耦合损耗的影响较小，而角度α和β变化时产生的耦合损耗主要是由附加横向位移引起的，单纯的角度变化对耦合损耗的影响极小。若要求对准偏差损耗低于0.5 dB，则横向位错与纵向间距的容差范围分别为-1~1 μm和-20~20 μm。本研究为后续自动耦合系统的研究提供参考。

Alignment coupling between polarization maintaining fiber and input end of Y-waveguide is studied. The influence of alignment deviation on coupling loss at five degrees of freedom is simulated by mode-field overlapping integral method, and an experimental scheme based on digital image is designed. The simulation results are consistent with the experimental data, which proves the feasibility of the experimental scheme. The results reveal that the transverse misalignments X and Y have the greatest influence on the coupling loss, while the vertical spacing Z has less influence on the coupling loss. And the coupling loss generated by the deflection angle α or pitch angle β is mainly caused by additional transverse displacement, while the mere change of angle has minimal impact on coupling loss. When the coupling loss is required to be under 0.5 dB, the tolerance range of transverse misalignment and vertical spacing should be restricted within -1 μm to 1 μm and -20 μm to 20 μm, respectively. The conclusions provide references for subsequent research on automatic alignment system.