中文摘要：

对椭圆芯保偏光纤的模间干涉现象进行了仿真研究，得到了其干涉输出光强分布同模间相位差之间的关系。将一种椭圆芯保偏光纤进行等面积矩形变换后，通过马卡梯里近似方法对两个低阶模式LP01模和LP^even 11模的传输特性及传播常数进行了数值计算，得到了归一化传播常数和归一化截止频率之间的关系。通过实验得到了两个模式之间干涉模斑远场图样，表明椭圆芯保偏光纤的模间干涉特性可以应用于应力、电压等的测量。模间干涉将传感臂和参考臂集于一根光纤中，具有很好的抗环境干扰能力。

英文摘要：

The intermodal interference in Elliptical-core Polarization Maintenance Fiber（E-core PMF） is investigated in this paper,and the relationship between interference output intensity distribution and phase difference of LP01 and LP11^even mode is given. With rectangle perturbation approach of E-core PMF,the mode characteristics and propagation even constant of an E-core PMF＇s LP01 and LP11 mode are calculated quantitatively with Marcatili method. The relationship plot of normalized propagation constant and normalized cutoff frequency is got. An experiment is set up to demonstrate the intensity distribution of far field interference output from the E-core PMF. The result shows that the intermodal interference in E-core PMF can be used in strain and voltage measurement. Intermodal interference integrates sensor arm and reference arm in a piece of single fiber, and it has inherent immunity to environment disturbance.