Research and application of multi-channel SPR sensor cascaded with fiber U-shaped structure

Multi-channel fiber SPR sensor can realize the detection of multiple analytes and specific binding detection. In this paper, by controlling the curvature radius of U-shaped structure to adjust the working band of the sensor, a multi-channel fiber SPR sensor cascaded with fiber U-shaped structure was proposed and demonstrated. By employing the U-shaped structure with curvature radius of 1 mm and 5 mm, the dual-channel fiber SPR was fabricated and tested, the refractive index sensitivity is 1414 nm/RIU and 3687 nm/RIU, respectively. By using this dual-channel fiber SPR, glucose and sucrose were detected at the same time, the detection sensitivity is 0.172 nm/μg/ml and 0.738 nm/mg/ml, respectively. The proposed multi-channel fiber SPR sensor based U-shaped structure has the advantages of simple structure, convenient operation, and can be directly inserted into a narrow space for measurement, which has practical value for the simultaneous measurement of multiple parameters.