Design of a quad channel SPR-based PCF sensor for analyte, strain, temperature, and magnetic field strength sensing

This paper proposes a simple, fabrication-friendly, extremely low loss photonic crystal fiber sensor in accordance with the surface plasmon resonance. Our proposed sensor has a di-material plasmonic layer of 20 nm Gold (Au) and 10 nm Titanium Dioxide (TiO 2 ). Variations of the sensor's optical parameters are detected through the Finite Element Method of COMSOL Multiphysics (v. 5.5). After optimizing all cross-sectional parameters, the sensor model has gained maximum Amplitude Sensitivity and Wavelength Sensitivity of 4646.1 RIU −1 and 10,000 nm/RIU with 2.15 × 10 –6 RIU and 1.00 × 10 –5 RIU sensor resolutions, respectively, within 1.33–1.42 RI range for analyte sensing. Besides, a shallow maximum confinement loss magnitude of 0.8125 dB/cm at 1.43 RI was observed, indicating the possibility of having excellent sensor length. Moreover, decent sensitivities were obtained in terms of strain, temperature, and magnetic field strength (MFS) sensing with the corresponding maximum values of 4.0 pm/µε (0.004 nm/µε), 1.00 nm/°C, and 160 pm/Oe (0.16 nm/Oe), respectively. Our proposed sensor shows remarkable performance in sensing any minute alterations in analyte RI, strain, temperature, and MFS, making it a unique and significant addition to the scientific, biomedical, and industrial fields.