A sensor based on D-shaped photonic crystal fiber (PCF) with elliptical holes is designed and numerical studied by finite element method (FEM). The refractive index (RI) of analyte can be detected by using surface plasma resonance effect and optical fiber with elliptical holes can solve the phase matching problem. The size of central hole, the major axis of the two elliptical holes near polishing plane in first layer and polishing depth are adjusted to explore the influence of these parameters on wavelength sensitivity and amplitude sensitivity of the sensor. Polishing depth has a great influence on wavelength sensitivity of the sensor. As a result, higher sensitivity is obtained with larger polishing depth in the range of 1.33–1.39 and smaller polishing depth is more suitable with RI changing from 1.39–1.42. The wavelength sensitivity of the designed sensor is 10,200 nm/RIU, which means the designed sensor has a promising application prospect.
Design of diamond-shape photonic crystal fiber polarization filter based on surface plasma resonance effect