Novel High-Temperature Fiber-Optic Pressure Sensor Based on Etched PCF F-P Interferometer Micromachined by a 157-nm Laser

A self-enclosed fiber-optic Fabry-Perot (F-P) cavity is created by splicing a single-mode fiber to a photonic crystal fiber (PCF) with a precise hole micromachined by a 157-nm laser at the end face of the PCF. Furthermore, such a F-P cavity is etched chemically and its high-temperature and pressure responses are investigated experimentally. The pressure sensitivity is ~54.7 pm/MPa and the temperature sensitivity is ~0.45 pm/°C. The proposed sensor could offer some excellent features such as good high-temperature stability, low cross-sensitivity between pressure and temperature, ease of mass-production, making it attractive for pressure measurement under high-temperature.