Fig. 1. Structural diagram of MS-FPI

Fig. 2. Micrograph of MS-FPI

Fig. 3. Interference spectra of MS-FPI under different statuses, the inset indicates the bending status of the corresponding interference spectrum

Fig. 4. Interference spectra of MS-FPI under different temperatures, the inset is the partical enlargement of the waveform

Fig. 5. Schematic diagram of wavelength demodulation system based on MS-FPI

Fig. 6. Setup of static wavelength demodulation experiment

Fig. 7. Results of static wavelength demodulated experiment

Fig. 8. Linear fitting result of the demodulated outputs and wavelengths

Fig. 9. FBG pulse wave of the same volunteer. (a) Pulse wave obtained by commercial interrogator; (b) original pulse wave output by the designed demodulation system; (c) processed pulse wave

Fig. 10. Comparison of pulse waves of FBG and PPG. (a) Volunteer A; (b) volunteer B