Research on modular interference of elliptical-core polarization maintenance fiber

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 LPeven11 mode is given. With rectangle perturbation approach of E-core PMF, the mode characteristics and propagation constant of an E-core PMF's LP01 and LPeven11 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.