Ultra-broadband and highly sensitive surface plasmon resonance sensor based on four-core photonic crystal fibers

An ultra-broadband surface plasmon resonance (SPR) sensor with high sensitivity adopting four-core photonic crystal fiber is designed. The impacts of fiber structure parameters on the sensing performance are theoretically studied in detail. The investigation results demonstrate that, the average wavelength sensitivity of our proposed sensor is up to 1.135 x 10(4) nm/refractive index unit (RIU) within the ultra-broad wavelength range of 1.548-2.683 mu m when the refractive index (RI) of analyte varies in a large range of 1.423-1.523. Furthermore, the maximum amplitude sensitivity of 550 RIU-1 is achieved if RI changes from 1.423 to 1.433. Therefore, the proposed sensor can work both in the telecommunication window, and the mid-infrared wavelength regime.