Fiber Optic Fabry-Perot Pressure Sensor With Embedded MEMS Micro-Cavity for Ultra-High Pressure Detection

A fiber-optic Fabry-Perot pressure sensor with embedded micro-electromechanical system (MEMS) micro-cavity for ultra-high pressure detection is demonstrated. The embedded-type structure (ETS) is first proposed and analyzed to meet the requirements of ultra-high pressure detection. The geometry parameters of sensor have been optimized by analyzing mechanical and optical characteristics. From the analysis results based on the ETS, an ultra-high pressure sensor is fabricated and experimentally demonstrated for ultra-high pressure detection. The ultra-high pressure experiment illustrated response relationship between the absolute phase and pressure in the range of 2-120 MPa, and fullscale (FS) errors less than 0.079% F.S. at room temperature. The other characteristics index of sensor such as pressure sensitivity, hysteresis error, and temperature's influence factor are superior to 1.071 rad/MPa, 1.397%, and 2.665 × 10 ^-3 rad/°C, respectively. The transient response time of system is 0.27 s. The sensor can be used for ultra-high pressure detections, which is necessary in deep-sea and oil exploration.