Highly Sensitive Detection of Refractive Index and Temperature Based on Liquid-Filled D-Shape PCF

A plasmon resonance sensor (SPR) based on D-shape photonic crystal fiber (PCF) is proposed to realize the simultaneous measurement of refractive index (RI) and temperature. The upper surface of the D-shape PCF is coated with gold film as a plasmon resonance excitation material for the detection of RI. An air hole near the fiber core is coated with gold film and filled with temperature-sensitive liquid ethanol to detect temperature. Results show that the y-polarized peaks supported only shift with RI variation and is unaffected by the temperature floating. Similarly, the x-polarized peak is only influenced by the change of temperature in the external environment. The proposed sensor achieved wavelength sensitivity of 3940nm/RIU with analyte RI between 1.35 and 1.40, and 1.075nm/°C of temperature ranging from 20°C to 60°C. The proposed liquid-filled D-shape photonic crystal fiber will have potential application in solving the problem of cross-sensitivity of temperature and RI.