Side-Opening Grapefruit Fiber-Based SPR Sensor for Simultaneous Measurement of Refractive Index and Temperature

A novel side-opening grapefruit fiber-based SPR sensor is designed to realize simultaneous measurement of refractive index (RI) and temperature. The open section of the grapefruit fiber is coated with a gold layer, which can support two main resonance peaks. The variations of RI and temperature can influence the coupling efficiency between core-guided mode and plasmon mode, thus lead to the two peaks shifts that can be used to determine the variations of RI and temperature. Simulation results demonstrate that the RI coefficients of Peak I and Peak II are 1400 nm/RIU and 226 nm/RIU, respectively. The temperature coefficients of Peak I and Peak II are 34 pm/°C and 527.2 pm/°C, respectively.