建立了基于波长调制的Kretschmann结构表面等离子体共振(SPR)传感器系统中整形光路和探测光斑直径与会聚角关系的理论模型。分析了探测光束会聚角对SPR传感器共振波长、共振曲线半峰全宽和共振峰深度的影响。随着探测光束会聚角的减小，共振波长增大，共振曲线的半峰全宽减小，共振峰深度增大，传感器的抗干扰能力增强，系统分辨率提高。通过实验对此进行了验证，考虑会聚角时实验与仿真结果符合得较好；会聚角从0.8°减小到0°时，共振波长从662 nm减小到623 nm，共振曲线半峰全宽从157 nm减小到117 nm，共振峰深度从70.5%增大到93.3%。

In the surface plasmon resonance (SPR) sensor system with Kretschmann configuration based on wavelength modulation technology, the theoretical model of the influence of beam reshaped system and the beam diameter on the convergence angle is built. The influence of convergence angle of probe beam on resonance wavelength, the full width at half maximum (FWHM) and the depth of resonance peak is analyzed. As the convergence angle decreases, the resonance wavelength is enhanced, the FWHM is reduced, and the depth of resonance peak is enhanced. As a result, the capacity of resisting disturbance is enhanced, and the system resolution is enhanced. It is confirmed by experiment, and the experimental result fit well with the simulated one when considering the influence of convergence angle. When the convergence angle varies from 0.8° to 0°, the resonance wavelength varies from 662 nm to 623 nm, the FWHM is reduced from 157 nm to 117 nm, and the depth of resonance peak is enhanced from 70.5% to 93.3%.