RI and temperature sensor based on hybrid sensing mechanism of SPR and MZI using a four-core fiber

A dual-parameter sensor based on a hybrid sensing mechanism of surface plasmon resonance (SPR) and Mach–Zehnder interference (MZI) using a four-core fiber (FCF), is proposed and implemented. The designed sensor is fabricated by cascading a sandwich structure of the FCF, multimode fiber and lead-in/out single-mode fiber. The gold-coated FCF as the critical component, enabling the excitation of the SPR and MZI for measuring refractive index (RI) and temperature. The proposed sensor exhibits a high RI sensitivity of 2091 nm/RIU and a temperature sensitivity of 0.0398 nm/°C. The proposed dual-parameter sensor based on FCF provides a new insight for the design of fiber SPR sensor, which can be used to measure multiple physical parameters in various fields such as biochemistry, gene diagnosis, environmental monitoring, and so on.