Fig. 1. Schematic diagram of system structure

Fig. 2. Schematic diagram of time-division multiplexing detector array

Fig. 3. Schematic diagram of optical pulse sequence returned by time-division multiplexing detector array

Fig. 4. Flow chart of heterodyne demodulation of interference signal

Fig. 5. Background curve of system noise measured in laboratory environment

Fig. 6. Maximum demodulated signal amplitude and dynamic range curve

Fig. 7. Physical drawing of optical fiber detector array

Fig. 8. Schematic diagram of underground position deployment of optical fiber detector array

Fig. 9. Time-domain waveform curves and signal characteristic distribution of microseismic signal

Fig. 10. Time-frequency domain diagram of typical microseismic signal