Fig. 1. Schematic and equivalent diagrams of bended ExTFG. (a) Schematic diagram of bended ExTFG; (b) equivalent diagram of bended ExTFG

Fig. 2. Modal analysis diagrams of cantilever ExTFG based on ANSYS finite element analysis. (a) First-order vibration mode; (b) second-order vibration mode

Fig. 3. Frequency response of first-order and second-order vibration modes of ExTFG sensor with different lengths (inset is enlarged view of frequency response)

Fig. 4. Light path diagram of reflective ExTFG, and polarization dependence spectrum of reflective ExTFG at C+L band. (a) Light path diagram of reflective ExTFG; (b) polarization dependence spectrum of reflective ExTFG at C+L band

Fig. 5. Schematic of vibration sensing system and magnified view of ExTFG sensing probe. (a) Schematic of vibration sensing system; (b) magnified view of ExTFG sensing probe

Fig. 6. Amplitude-frequency response of sensor with different lengths at first-order vibration mode. (a) TE mode; (b) TM mode

Fig. 7. Amplitude-frequency response of first-order and second-order vibration modes of reflective ExTFG with 3.8 cm length

Fig. 8. Response of output amplitude of reflective ExTFG versus input acceleration at different frequencies of 105, 115, and 125 Hz. (a) TE mode; (b) TM mode

Fig. 9. Sensing characteristics of reflective ExTFG when L=2.9 cm. (a) Frequency domain response diagram of 3 dB resonant peak at 115 Hz for TE mode; (b) frequency domain response diagram of 3 dB resonant peak at 105 Hz for TE mode; (c) frequency domain response diagram of 3 dB resonant peak at 115 Hz for TM mode; (d) frequency domain response diagram of 3 dB resonant peak at 105 Hz for TM mode

Table 1. Comparison of simulation results and theoretical values of natural frequencies for first-order and second-order vibration modes