Reflective Optical Fiber SPR Sensor for Simultaneous Measurement of Glucose Concentration and Temperature

To achieve a compact and robust structure, a reflective optical fiber surface plasmon resonance (SPR) sensor is proposed for the simultaneous measurement of glucose concentration and temperature. The fiber probe uses the multimode optical fiber-single mode optical fiber-multimode optical fiber (MSM) heterojunction structure, in which the region with a gold film is used to sense glucose concentration, while the other region with a gold film and a polydimethylsiloxane@gold (PDMS@Au) composite is used to sense temperature. A silver film for light signal reflection is coated on the end face of the fiber probe to improve the signal-to-noise ratio (SNR). The sensor successfully overcomes cross-sensitivity and achieves sensitivities of 3.05 nm/% and − 1.69 nm/°C for glucose concentration and temperature, respectively. The proposed sensor can realize high-precision sensing of glucose and other biological analytes with temperature compensation. In addition, the reflective sensing structure makes the system compact and flexible, which enables remote detection and in-situ monitoring. The proposed sensor has a wide range of applications in the fields of food safety, biochemistry, and environmental monitoring.