High sensitivity refractive index sensor based on cascaded core-offset splicing NCF-HCF-NCF structure

In this paper, a high sensitivity refractive index sensor based on cascaded core-offset splicing structure with no-core fiber (NCF)-hollow core fiber (HCF)-no-core fiber (NCF) is proposed. The sensor consists of single mode fiber (SMF) cascaded with no-core fiber, and then the no-core fiber and hollow core fiber are cascaded, which is in core-offset splicing NCF-HCF-NCF structure. The simulation results show that with the increase of environmental refractive index, the transmission spectrum is red shifted. The experimental results show that the refractive index sensitivity is up to 245.67149 nm/RIU during the range of 1.3355 ∼ 1.3625. The sensor has the advantages of compact structure, simple fabrication and high sensitivity, so it can be widely used in the field of refractive index sensing.