Pressure-insensitive Low-density Polyethylene Diaphragms-based Optical Fiber Temperature Sensors

Highly sensitive measurement of temperature in harsh environments has seen considerable research. This paper presents an optical fiber temperature sensor based on diaphragms, which utilizes the change in the Fabry–Perot (FP) cavity length due to the deformation of the diaphragm by thermal expansion to realize temperature sensing. Low-density polyethylene with an air permeability diaphragm is used to achieve pressure insensitivity. The experimental results indicate that the sensors are insensitive to pressure and sensitive to temperature. The cavity length sensitivity is 0.626 µ m at 15 to 50 ∘ C. The wavelength sensitivity can reach 12.922 nm/ ∘ C, thereby allowing for precision temperature monitoring in harsh environments.