Design and analysis of a high-sensitivity fan-shaped photonic crystal fiber sensor based on surface plasmon resonance

A high-sensitivity fan-shaped photonic crystal fiber sensor based on surface plasmon resonance (SPR) is proposed and theoretically analyzed. In order to excite SPR, Indium Tin Oxide (ITO) is deposited on the arc area. The proposed sensor is operated within the large near infrared region (1000–2000 nm). The sensing performance and coupling characteristics are thoroughly explored through finite element method. Simulation results show that the sensor exhibits an optimum wavelength sensitivity (WS) of 10,500 nm/RIU and resolution of 9.524 × 10−6 ‍RIU. The best amplitude sensitivity can be up to 144.43 RIU−1, corresponding to the resolution of 6.92 × 10−6 RIU. Also, an ideal figure of merit (FOM) of 73.32 RIU−1 can be achieved when the analyte refractive index (RI) is 1.386. In a large wavelength range, the sensor shows a distinctly sharp loss peak that is easy to conduct and monitor. The sensor can detect the RI of unknown analyte in the range of 1.336–1.396. The sensor has a promising stability in fabrication tolerance. By adjusting the structure parameters, it shows that solely the thickness of ITO layer has effect on sensing ability. Slight difference of other parameters can barely influence the sensor. Application of the proposed sensor can be found in multiple fields such as bio-chemical sensing, food safety and environmental monitoring, etc.