Dual Sagnac Interferometer Distributed Optical Fiber Localization Method Based on Hilbert–Huang Transform

In order to solve the problem that dual Mach Zehnder (M-Z) interferometer system is easily affected by external environmental noise, a data signal-processing scheme based on Hilbert–Huang transform (HHT) proposed achieve high-precision location with distributed optical fibers. The polarization compensation module has built-in Sagnac which used stabilize state of interferometer. eigenmode function obtained empirical mode decomposition received two signals, and then Hilbert spectrum superimposing transform, so high-similarity curve caused vibration signal can be clearly intuitively extracted. information calculated cross-correlation delay estimation algorithm accurately obtain position information. experimental results show positioning accuracy reach ±11 m, sensing fiber length 15 km sampling rate 10 MHz. It proven technology high practical application value.