High sensitivity photonic crystal fiber sensor based on dual-core coupling with circular lattice.

• The sensor is capable of detecting a refractive index change of the liquid analyte ranging from 1.33 to 1.41. • The sensitivity of the sensor can reach a maximum of 22071 nm/RIU when the refractive index of liquid analyte is 1.41. • The performance of the sensor can be improved by optimizing its structural parameters. • It can easily be implemented for the manufacture of the proposed fiber sensor in actual production. A novel high-sensitivity circular dual-core photonic crystal fiber refractive index sensor is proposed in this paper. The effects of air hole spacing, liquid filled air hole diameter and cladding air hole diameter on its sensor sensitivity are analyzed in detail. The simulation results show that the liquid refractive index that the sensor can detect ranges from 1.33 to 1.41. By optimizing the geometric parameters, when the analyte refractive index is 1.33 and 1.41, respectively, the minimum sensitivity of this PCF sensor is 8929 nm/RIU, and the maximum value can reach 22071 nm/RIU. Due to its high sensitivity and simple structure, this PCF sensor can be widely used for chemical detection and biomolecule detection. [ABSTRACT FROM AUTHOR]