Surface plasmon resonance sensor based on D-shaped photonic crystal fiber with two micro-openings

A high sensitivity refractive index sensor based on D-shaped photonic crystal fiber with surface plasmon resonance (SPR) is designed and analyzed by a full-vector finite element method. The side-polished fiber has two micro-openings of the same size, and the gold film is deposited on the polished surface between them. The D-shaped fiber is completely immersed in the analyte whose different refractive indices vary from 1.31 to 1.37. In the proposed sensor, the coating of the gold film and the filling of the analyte can be achieved on the outer surface of the fiber. Numerical simulation results show that the maximum sensitivity can reach 11750nm/RIU, corresponding to a resolution of 8.51 x 10(-6) RIU in this sensor. Due to the simple structure, convenient detection and ultrahigh sensitivity, the proposed SPR sensor can be widely used in environmental, biological and biochemical sensing fields.