Fig. 1. Schematic diagram of MPF demodulation based on frequency-time transform

Fig. 2. Schematic diagram of time-domain refinement algorithm

Fig. 3. Experimental setup of MPF based interrogation system for fiber Bragg grating array

Fig. 4. Spectrogram and time-domain diagram of system. (a) Radio frequency response curves of fiber Bragg grating array; (b) time-domain impulse response obtained by IDFT

Fig. 5. Time-domain response curves of FBG 3 under different strain values

Fig. 6. Time-domain impulse responses obtained by two frequency-time transform algorithms under different strain values. (a) Time-domain refinement algorithm; (b) zero-padding algorithm

Fig. 7. Comparison of wavelength demodulation values obtained by two frequency-time transform algorithms and measured ones under different strain values. (a) Time-domain refinement algorithm; (b) zero-padding algorithm

Fig. 8. Comparison of wavelength interrogation values obtained by time-domain refinement algorithm and measured ones under different sampling points. (a) N=1000; (b) N=10000