Surface Plasmon Resonance Optical Fiber Sensor for Refractive Index Detection Without Temperature Crosstalk

The surface plasmon resonance (SPR) sensor based on the optical fiber Mach–Zehnder (MZ) interference is proposed for refractive index (RI) detection without temperature crosstalk. The MZ interference is made by inserting a section of photonic crystal fiber (PCF) between two multimode optical fibers, what is noteworthy is that PCF is one side coated with gold film, the SPR effect is formed on the side with gold film coated and adopted for RI measurement, and the MZ interference is formed on the other side without gold film coated and adopted for temperature measurement. Therefore, the SPR effect and the MZ interferometer are coexistence in one compact sensor. The sensitivity of temperature and RI are 0.34 nm/°C and 1947.405 nm/RIU, respectively. The proposed sensor has the advantages of small size, easy fabrication, and high performance, which is suitable for multiparameter and distributed measurement.