Fig. 1. Structural diagrams of interferometric fiber sensing time-division multiplexing system with experimental schemes of two different sets of sensor interferometers and reference interferometers shown in insets Ⅰ and Ⅱ

Fig. 2. Flow chart of phase demodulation

Fig. 3. Sound and vibration isolation box. (a) Appearance of sound and vibration isolation box; (b) structural diagram of sound and vibration isolation box

Fig. 4. Phase demodulation results before and after processing by ellipse fitting algorithm. (a) Before processing by ellipse fitting algorithm; (b) after processing by ellipse fitting algorithm

Fig. 5. Results of sensor interferometer and reference interferometer before and after ellipse fitting. (a) Result of reference interferometer; (b) result of sensor interferometer

Fig. 6. Phase demodulation results of sensor interferometer and reference interferometer in one group.

Fig. 7. Phase demodulation results calculated by ellipse fitting method and reference compensation method. (a) Channel 1; (b) Channel 2; (c) Channel 3; (d) Channel 4

Fig. 8. Square wave signal with peak-peak value of 20 nε acting on sensing arm of sensor interferometer