A Highly Sensitive H-Shaped Optical Fiber Sensor for Monitoring Blood Glucose Level

The present research addresses a new kind of H-shaped optical fiber sensor (OFS) based on the surface plasmon resonance (SPR) phenomenon for sensing blood glucose levels in diabetic patients. The sensor is designed to be incorporated between D-shaped and U-shaped structures to form an H-shaped structure. The proposed sensor is numerically modeled and analyzed by exploiting the finite element method (FEM). The mainstay of this study is to analyze the coupling of plasmonic and core modes to get a maximum confinement loss, which is the main sensing mechanism through the evanescent field. The structural parameters, including the thickness of the Au layer, height of the fiber, width of the channel, penetration depth of the channel, and doping concentration of the core, are judiciously optimized to attain maximum sensing performance. The sensor confers a convenient and easy way to identify diabetic patients by observing the resonance wavelength. The proposed sensor numerically achieves a maximum sensitivity of $0.005~\mu $ m/mmol/L, equivalent to 4762 nm/RIU. Its figure of merit (FoM) and resolution are $59.523~{\text {RIU}}^{-{1}}$ and ${2.10} \times 10^{-5}$ RIU, respectively. Moreover, the designed structure is simple and easily fabricated, making it a suitable candidate for biomedical applications.