A core-offset hetero structured optical fiber based surface plasmon resonance sensor

A core-offset hetero structured optical fiber was fabricated and proposed for surface plasmon resonance (SPR) sensor. The hetero structure was constituted by a multimode fiber (MMF), core-offset single mode fiber (SMF), and MMF, which are spliced together by a fusion splicer. The effect of the size of core-offset on the RI sensing performance was studied experimentally. The results show that compared with the traditional MMF-SMF-MMF structure, the sensitivity of the proposed structure can be improved, and the highest sensitivity can reach to 6760.17 nm/RIU when the core-offset is 9 μm. The sensor is easy to fabricate, simple structure.