Fig. 1. Static strain schematics of Ex-TFG. (a) Axial strain; (b) bending strain

Fig. 2. Transmission spectra of Ex-TFG. (a) Polarization dependence spectrum of Ex-TFG in C+L bands; (b) schematic of spectral change of Ex-TFG loaded with vibration for TE mode

Fig. 3. Axial strain response of Ex-TFG. (a) Spectrum of TE mode under axial strain (inset: TM mode); (b) axial strain response sensitivities of TE and TM modes

Fig. 4. Bending strain responses of Ex-TFG. Spectra of bending strain responses of (a) TE mode and (b) TM mode; corresponding (a) light intensity changes and (d) wavelength shifts of TE mode and TM mode

Fig. 5. Experimental system diagram of low frequency vibration sensing based on cantilever beam

Fig. 6. Frequency response characteristics of PZT. (a) Response curve of PZT output shift versus frequency; (b) response curve of PZT vibration acceleration versus frequency

Fig. 7. Frequency response diagrams of Ex-TFG resonance peaks at different percentages points. (a) TE mode; (b) TM mode

Fig. 8. Amplitude response versus input voltage at different vibration frequencies of 65, 68, 75, and 160 Hz. (a) TE mode; (b) TM mode

Fig. 9. Frequency response stabilities for TE mode and TM mode

Fig. 10. (a) Time domain signal at 3 dB point of TE resonance peak of Ex-TFG when cantilever beam with Th=0.3 mm is driven by sinusoidal signal with input voltage of 5 V and frequency of 68 Hz; (b) frequency spectra at 25%, 50%, 75%, and 100% wavelength points of TE resonance peak; (c) time domain signal at 3 dB point of TM resonance peak of Ex-TFG when cantilever beam with Th=0.3 mm is driven by sinusoidal signal with input voltage of 5 V and frequency of 68 Hz; (d) frequency spectra at 25%, 50%, 75%, a

Fig. 11. Response curves when cantilever beam thickness Th is 0.3, 0.4, and 0.5 mm, respectively. (a) Response curves at 3 dB point of TE resonance peak; (b) frequency spectra of TE mode; (c) response curves at 3 dB point of TM resonance peak; (d) frequency spectra of TM mode