A Miniature Fabry–Pérot Interferometer for High Temperature Measurement Using a Double-Core Photonic Crystal Fiber

A miniature Fabry-Pérot interferometer is proposed and experimentally demonstrated for high temperature measurement. The device is fabricated by alignment splicing a short section of double-core photonic crystal fiber (DC-PCF) to the lead-in single mode fiber. Due to the optical path difference of reflective light from splicing region and end-face of DC-PCF, a well-defined interference spectrum is obtained based on ~ 72.3 μm-long cavity. Experimental results indicate that the proposed sensor has a considerable temperature sensitivity of 13.9 pm/°C in the measurement range of 30 °C-900 °C. The proposed sensor has advantages of small size and high stability, and so on, making it a good candidate in harsh high temperature environment with limited-space.