Eliminating the influence of polarization instability using time-wavelet energy spectrum for FBG-FP static-strain sensing

The fluctuation of polarization may cause wrong demodulation results in high-resolution static-strain sensing based on FBG-FP. This paper presents a polarization-insensitive demodulation algorithm using time-wavelet energy spectrum for single mode fiber (SMF) based FBG-FP sensor. This method can eliminate the influence of polarization instability effectively. Time-wavelet energy spectrum is calculated to get the energy distribution of the reflectance spectrums of FBG-FP on the timeline. The maximum value of the energy distribution is used to obtain the strain signal. In the laboratory, a high-resolution strain demodulation result without polarization controller is obtained.