Flexible fiber optic sensor for dual parameter perception of liquid level and temperature

Abstract In this paper, a flexible optical fiber for two-parameter measurement of liquid level and temperature is presented. The flexible fiber is composed of polyurethane membrane and spherical microfiber few mode fiber (FMF) . It has excellent mechanical properties and thermal stability. By converting the change of liquid level into the change of static liquid pressure of polyurethane diaphragm, the performance of the sensor is analyzed by finite element method (FEM) and beam propagation method (BPM). The sensitivity of the liquid level sensor is 0.54534 nm/mm, and the sensitivity of the liquid level sensor is increased about 5 times. In order to eliminate the temperature interference, the temperature decoupling scheme is studied in this paper. The problem of cross sensitivity is solved by discussing the interference of temperature on double wave peaks. It has a broad prospect in the field of fuel level monitoring and control.