Fig. 1. Schematic diagram of demodulator

Fig. 2. (a) Peak-seeking threshold; (b) Comparison of peak-seeking threshold

Fig. 3. (a) Original spectrogram; (b) Histogram of spectral data

Fig. 4. Experimental system of FBG demodulation

Fig. 5. Peak light intensity-exposure cycle relationship of single grating fiber

Fig. 6. Peak light intensity-exposure cycle relationship of multi-grating fiber

Fig. 7. Curve diagram of peak light of intensity-center wavelength standard deviation

Fig. 8. Adaptive demodulation spectrogram. (a) Exposure cycle/100 ns：234.4; (b) Exposure cycle/100 ns：304; (c) Exposure cycle/100 ns：503.1; (d) Exposure cycle/100 ns：659.6; (e) Exposure cycle/100 ns：967.2, (f) Exposure cycle/100 ns：2832.6; (g) Exposure cycle/100 ns：3881.2; (h) Exposure cycle/100 ns：5562.8

Table 1. Comparison of different fitting methods of single grating fiber peak light intensity-exposure cycle

Table 2. Linear fitting results of multi-grating fiber peak light intensity-exposure cycle

Table 3. Experimental results of adaptive demodulation algorithm