提出了一种基于模间干涉原理的双空气孔保偏光子晶体光纤弯曲传感方法。采用有限差分光束传播法对保偏光子晶体光纤弯曲传输特性进行了仿真研究,给出了在弯曲调制时两个低阶偏振模干涉产生的双边瓣归一化光强与弯曲半径的关系,讨论了波长变化对弯曲传感灵敏度的影响,并对所设计的弯曲传感器进行了实验研究。研究结果表明:基于模间干涉技术的双空气孔光子晶体保偏光纤弯曲传感器在10~30 mm的弯曲半径范围内具有良好的线性度和检测精度。 A method based on the principle of intermodulation interference is proposed for the bend sensing of double air-hole polarization-maintaining photonic crystal fibers. The finite difference beam propagation method was used to simulate the propagation of the polarization-maintaining photonic crystal fibers. The relationship between the normalized intensity of the bilateral edges and the bending radius caused by the two low-order polarization mode interferences during bending modulation was discussed. The influence of the wavelength variation on the sensitivity of the bending sensor is also studied. The bending sensor designed is studied experimentally. The results show that the dual-aperture photonic crystal polarization-maintaining fiber bend sensor based on the inter-mode interference technique has good linearity and detection accuracy in the bending radius of 10-30 mm.