High amplitude sensitivity gold‐coated trichannel photonic crystal fibre for refractive index sensor

Abstract

Abstract We propose highly sensitive trichannel photonic crystal fibre (TCPCF) refractive index (RI) sensor based surface plasmon resonance (SPR). In this design, we have been integrated the sensing layer with thin gold metal deposited over the surface of the TCPCF for fabrication feasible and easy liquid infiltration. Then, Y‐shaped channel is formed through reducing the diametre of air holes for controlling the direction of light through photonic crystal fibre to attain high sensitivity. Also, effective coupling between surface plasmon polariton mode at the metal layer and the core‐guided mode is obtained by numerical simulation of finite element method. The optimized TCPCF sensor exhibits maximum amplitude sensitivity of 1938.5 RIU−1 and wavelength sensitivity of 11,000 nm.RIU−1 within the analyte range from 1.34 to 1.39. Further, we have achieved amplitude resolution of 5.2 × 10−6 RIU and wavelength resolution of 9.1 × 10−6 RIU. It is confirmed high detection accuracy for small changes in RI analyte. Moreover, high figure of merit of 623.9 RIU−1 is obtained for the proposed sensor. Therefore, the proposed TCPCF RI sensor can be utilized in the chemical, bio and gas sensing applications.

Keywords

• fibre optic sensors
• finite element analysis
• gold
• holey fibres
• optical fibre fabrication
• photonic crystals