Fig. 1. Fiber ring laser strain sensing system based on two-wave mixing demodulation. (a) Principle; (b) experimental installations

Fig. 2. Principle of TWM interferometer

Fig. 3. Influence of different optical path difference on wavelength demodulation signal at electric field intensity of 5.1 kV/cm

Fig. 4. Influence of different applied electric field intensities on wavelength demodulation signals at optical path difference of 4 mm

Fig. 5. Response of sensor system to dynamic signals at different frequencies. (a) 0.05 kHz; (b)0.20 kHz; (c) 29.00 kHz; (d) 83.00 kHz; (e) 243.00 kHz; (f) 464.00 kHz

Fig. 6. Impact signal demodulation experiment. (a) Waveforms of impact signals from different sensors; (b) wavelet analysis of impact signals from different sensors

Fig. 7. Multiplexing device for sensing systems. (a) Schematic of device simulation; (b) output spectrum of ring laser

Fig. 8. Demodulation signal multiplexed by TWM demodulator at different frequencies. (a) 2 kHz; (b) 5 kHz; (c) 19 kHz