LAUSR

Abstract A novel refractive index sensor based on surface plasmon resonance (SPR) is proposed in this paper, which is induced by coating a metal film on the surface of a section of D-shape-polished dual-core photonic crystal fiber (DC-PCF). The mechanism of SPR resonance and sensing principle are discussed theoretically. The sensing characteristics as a function of the polished angle, depth, the material of metal film, coating layer thickness are analyzed comprehensively. A DC-PCF with a 60° polished angle, 58.02 μm polished depth is fabricated with a silver coating layer of 70 nm thickness experimentally, which demonstrates that the refractive index sensitivity can be as high as 3580 nm/RIU in the refractive index range of 1.33–1.43.