Asymmetrical photonic crystal fiber based on the surface plasmon resonance sensor and analysis by the lower-birefringence peak method

Abstract

A lower-birefringence peak method is used to investigate a new birefringence photonic crystal fiber (PCF) based on the surface plasmon resonance (SPR) sensor with an asymmetrical configuration. The novel method can determine the resonance wavelength and resonance intensity by the appearance of the lower peak and overcome deficiencies of the reported zero-birefringence point method. Upper and lower gaps are designed in the air holes to enhance the birefringence of the sensor as well as coupling efficiency between the plasmonic mode and core-guided mode. The dependence of the sensing performance on the structure parameters is discussed considering the depth of penetration of the evanescent wave and location of light confinement analysis. A maximum spectral sensitivity of 16,700 nm/RIU can be obtained in a broad refractive index (RI) detection range from 1.33 to 1.42 and the corresponding RI resolution is 5.99×10−6RIU.