Simultaneous measurement of temperature and pressure with cascaded extrinsic Fabry–Perot interferometer and intrinsic Fabry–Perot interferometer sensors

This paper presents an approach for simultaneous measurement of temperature and pressure using miniaturized fiber inline sensors. The approach utilizes the cascaded optical fiber inline intrinsic Fabry–Perot interferometer and extrinsic Fabry–Perot interferometer as temperature and pressure sensing elements, respectively. A CO2 laser was used to create a loss between them to balance their reflection power levels. The multiplexed signals were demodulated using a Fast Fourier transform-based wavelength tracking method. Experimental results showed that the sensing system could measure temperature and pressure unambiguously in a pressure range of 0 to 6.895×105 Pa and a temperature range from 20°C to 700°C.