Fig. 1. Basic structure of compound fiber-optic Fabry-Perot pressure sensor

Fig. 2. Lissajous figure obtained by six-parameter ellipse-fitting algorithm

Fig. 3. Reflection spectrum of compound FP sensor with short cavity and interferometric signal for cavity filling with air

Fig. 4. Lissajous figure when interferometric signal has translation of τ=1.238 THz along frequency axis

Fig. 5. Demodulation system for fiber-optic Fabry-Perot sensor. (a) Schematic; (b) physical map

Fig. 6. Compound fiber-optic Fabry-Perot pressure sensor with short cavity. (a) Physical map; (b) SEM image

Fig. 7. Experimental setup for pressure sensing

Fig. 8. Experimental results of pressure sensing. (a) Reflection spectra for cavity filling with air under three kinds of pressure-loading conditions of 0.1, 0.3, and 0.5 MPa; (b) sensor cavity length versus pressure