Sensitivity Analysis of Fault Detection for Few-mode Fiber Links Based on Rayleigh Backscattering

In this paper, the fault detection sensitivity (FDS) analysis model for the splice fault of few-mode fiber (FMF) links under dynamic crosstalk conditions is constructed, which is based on the principle of FMF Rayleigh Backscattering. Under the condition of the cumulative effect of different modes of crosstalk, the variation trend of the loss characteristics of the fusion splicing fault and the FDS characteristics of the three-mode fiber LP01, LP11a and LP11b are analyzed, respectively. The simulation results show that as the modal crosstalk introduced by the axial misalignment of the fusion splice increases, the FDS of the LP11a and LP11b modes deteriorates higher than that of LP01 mode. At the same time, this paper build an FMF fusion fault detection system based on photon lantern and fiber circulators. The experimental results shows that the results are consistent with the simulation results, which shows the feasibility of the FDS analysis model under the cumulative effect of modal crosstalk in the FMF link.