Microstructured Fiber Sensor Based On Resonance Coupling Between Cladding Mode and Surface Plasmon Mode for Sucrose Determination

This paper proposes a microstructured fiber (MSF) sucrose-concentration sensor based on resonance coupling between cladding mode and surface plasmon mode. The proposed sensor possesses high sensitivity, low hysteresis, and good stability at room temperature. Theoretical analysis reveals the spectral resonance at the metal-MSF interface by finite element method (FEM), which has a unique response to the RI variation of the external medium. Experimentally, the MSF sensor can track concentration variations in a wide range of 0%–48.7% through wavelength interrogation. And the maximum sensitivity is 19.42 nm/% at highest concentration. These experimental results are very close to the theoretical predictions. Compared with previously reported optical sensors, the microstructured fiber sensor has excellent performances with wide response-range, high sensitivity and fine resolution. Further researches indicated that the proposed MSF sensor has low hysteresis within the range of 0.007 and good repeatability with fluctuations below 0.439% at room temperature. The MSF sensor will be one of the promising methods to determine the concentration for sucrose solutions.