High-precision optical fiber Fabry–Perot composite sensor for pressure and temperature

Simultaneous monitoring of pressure and temperature in the skull cavity, kidneys, and cardiovascular organs and sites is urgently needed during clinical consultation and minimum invasive procedures. In this paper, the pressure/temperature fiber Fabry–Perot composite sensor fabricated by the micro electro mechanical system (MEMS) technology was studied. A variable step size fast Fourier transform-Minimum Mean Square-Error (FFT-MMSE) cavity length demodulation algorithm was proposed. This improved the demodulation accuracy and the rate of the cavity length signal. The experimental results showed that the optical fiber Fabry–Perot composite sensor had good response characteristics for pressure and temperature. It could maintain good linearity in the pressure measurement range of 0∼14 kPa and the temperature measurement range of 35∼50 °C. The pressure sensitivity was 9.811 nm/kPa, the temperature sensitivity was 1.707 nm/°C, and the temperature cross-sensitivity was 27.6 Pa/°C. The sensor has the characteristics of small size, fast response speed, high sensitivity, and strong stability. So it has great application potential in the field of biological medicine.