A dual-parameter Na-based PCF sensor with wide sensing bandwidth based SPR effect

Abstract Wide sensing bandwidth is a prerequisite for dual-channel sensors to have a wide detection range and high sensitivity. To obtain a dual-channel optical fiber sensor with wide sensing bandwidth, a Na-based photonic crystal fiber sensor based on the surface plasmon resonance effect is proposed. The proposed sensor structure is numerically analyzed by finite element method. The sensor builds the fiber core in the center of the fiber, chooses alkali metal Na as the plasma material to stimulate the SPR effect, and polymethyl methacrylate and polydimethylsiloxane (PDMS) will be coated on the Na film as the protective layer. As a temperature-sensitive material, PDMS also takes into account the role of constructing temperature-sensing channels. The sensor bandwidth covers 600–1700 nm. The results show that when the RI range of the measured object is 1.33–1.42, the maximum sensitivity of the refractive index sensor is 11100 nm/RIU, and when the temperature range of the measured object is −40–20 °C, the maximum sensitivity of the temperature sensor is 6.4 nm/°C. Meanwhile, the loss peak of the sensor has a lower half-height width and greater detection accuracy. It has a good application prospect in the fields of biosensing and environmental monitoring.