Single-mode eccentric-core D-shaped photonic crystal fiber surface plasmon resonance sensor

A single-mode eccentric-core D-shaped photonic crystal fiber (PCF) surface plasmon resonance (SPR) sensor is proposed and comprehensively investigated based on Finite Element Method (FEM). The critical properties of the sensor such as single mode regimes, beam spot size, and confinement losses are all tailored for more practical network-integrable PCF SPR sensor with high coupling efficiency using commonly used single-mode optical fibers. The sensor has analyte Refractive-Index (RI) detection range between 1.330 and 1.420 with maximum sensitivity of 21200 nm/Refractive-Index-Unit (RIU), maximum Figure-of-Merit (FOM) of 294 RIU⁻¹, maximum resolution of 4.72 × 10^-6 RIU for analyte refractive index change of 0.005 with the finest Full-Width at Half-Maximum (FWHM) of 29 nm, and a maximum confinement loss of 14 dB/cm. The sensor exhibits high linear response at low analyte RI regime between analyte index 1.330 and 1.370. The proposed sensor design can be fabricated using comparatively simpler stack-and-draw method which is based solely on standard circular glass capillaries and solid rods.