A Temperature and Pressure Simultaneous Measurement Sensor Based on Silicone Oil Encapsulated Hollow Core Photonic Crystal Fiber Cascading With Silica Membrane

In this study, we propose an optical fiber sensor by cascaded-integrating a silicone oil encapsulated hollow-core photonic crystal fiber (HC-PCF) with a silica membrane for the simultaneous measurement of temperature and pressure. The temperature variation induces a refractive index change of the silicone oil filled in the external environment of HC-PCF, leading to its spectral variations and enabling the temperature measurement. The deformation of the silica membrane under pressure results in a dynamic change in the optical path length, thereby causing the variations in the interference pattern. Experimental results demonstrate a temperature sensitivity of 0.083 nm/°C, with an error of only 0.048 °C caused by spectral drifting. Additionally, the pressure sensitivity is determined to be 0.409 nm/MPa. The cross-sensitivity between temperature and pressure measurements is eliminated by establishing a sensing matrix, to enable the synchronous measurement of both parameters. The proposed sensor exhibits the compact structure, high sensitivity and excellent repeatability, providing theoretical and technical references for the development of dual-parameter optical fiber sensors.