Multi-parameter measurement sensor based on an MMF–TCF–MMF structure

A multi-parameter measurement sensor based on a multimode fiber–thin-core fiber–multimode fiber structure has been designed and fabricated in this study. The structure combines Mach–Zehnder interference (MZI) with surface plasmon resonance (SPR) to realize simultaneous measurement of refractive index, temperature, and curvature. A MZI is constructed by fusion-splicing a thin-core fiber between two multimode fibers, with a silver coating deposited on the TCF to excite SPR. Experimental results showed that the MZI and SPR had a refractive index sensitivity of 3235.12 nm/RIU in the range of 1.333–1.384 RIU, a temperature sensitivity of 78.4 pm/°C in the range of 20–80°C, and a curvature sensitivity of −2.717nm/m −1 in the range of 0.4898−1.2961m −1 . Multi-parameter measurement is achieved through a sensing matrix, and this sensor has the advantages of small size, simple fabrication process, and high sensitivity. Therefore, this sensor has certain application values in environmental monitoring, biomedical, and other fields.