Highly Sensitive Dual-core Photonic Crystal Fiber Based on a Surface Plasmon Resonance Sensor with Gold Film

A highly sensitive surface plasmon resonance (SPR) sensor comprising a dual-core photonic crystal fiber (PCF) is designed to detect minute changes in analyte refractive indices (RIs) between 1.33 and 1.42. In order to simplify the fabrication process and analytical protocol, a gold film is deposited on the external surface of the fiber to excite surface plasmon polaritons (SPPs). The larger diameter air holes are used in the photonic crystal fiber (PCF) cladding, which not only simplifies the actual production, but also makes the energy of the core more concentrated, and can more fully generate surface plasmon resonance with surface plasmon polaritons (SPPs). The dual-core PCF-SPR sensor is analyzed by the finite-element method (FEM), and the various structural parameters are investigated systematically and optimized. The optimized PCF-SPR sensor shows a maximum wavelength sensitivity of 29,500 nm/RIU and resolution of 3.39 × 10−6 RIU.