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We propose a novel dual-channel fiber surface plasmon resonance (SPR) sensor based on a metalized core. Using a polymer, the cladding and coating layer of the sensor coated with a metal sensing film are restored. The parameters of the sensor are determined after studying the influence of different polymers and sensing films on the dynamic range and sensing sensitivity. A silver film coated with UV-curable adhesive and a gold film coated with polydimethylsiloxane (PDMS) with respective sensing sensitivities of up to 1.39 and 1.48 nm/°C are selected after optimization to construct the dual-channel sensor. A dual-channel fiber SPR temperature compensation refractive index sensor with improved accuracy is then constructed with a 20-nm gold film for the refractive index sensing unit and a 50-nm gold film coated with PDMS for the temperature sensing unit. Owing to its complete fiber structure, the SPR sensor has good mechanical properties and high practical value, and it can be easily applied to real-time temperature measurements and temperature compensation in various fields.

The fiber surface plasmon resonance (SPR) sensor is widely used in high-sensitivity refractive index detection, and there are few reports on SPR sensors used for strain measurement. In this paper, we propose and demonstrate an S-type fiber strain sensor based on SPR. The simulation and testing results indicate that the smaller the vertical axis offset of S-type fiber is, the larger the incidence angle of SPR is, and the closer the working band of SPR is to the shorter wavelength direction. By electrofusion, we fabricated an S-type structure on the single-mode fiber, and by the S-type structure, the high-order cladding mode was excited. A 50 nm gold film was coated on the surface of the fiber cladding behind the S-type structure. The evanescent field of the cladding mode contacted the gold film to produce SPR, and the strain can change the vertical axis offset of the S-type fiber and further change the incidence angle of SPR; hence an S-type fiber strain sensor based on SPR was realized. When the refractive index of the ambient medium is 1.345 RIU, the vertical axis offset and length of the S-shaped structure are 87 and 501 µm, respectively, the resonance wavelength of the fiber SPR strain sensor changes from 648.06 to 631.77 nm with a strain detection range of 0 − 1200 µ ε , and its sensitivity is − 14.38 p m / µ ε . The proposed sensor provides a new solution for the strain measurement of the fiber SPR sensor, which is expected to be used in the fields of engineering, health monitoring, and early warning.

Cladding fiber surface plasmon resonance (SPR) sensor has few structures, and clad SPR sensor based on S-type fiber was proposed in this paper. A new type of fiber cladding SPR sensor was formed by electrofusing an S-shaped structure on the fiber to couple the light in the fiber core to the cladding. In this paper, the effects of fiber parameters on the performance of the sensor were studied by simulation and experiment. Based on the conclusion that the smaller the core diameter is, the closer the working band of SPR resonance is to the long wavelength, and the geometric characteristics that the multimode fiber can receive the fiber cladding light of the small core diameter less mode fiber, a dual channel SPR sensor with double S-type fiber cascade was proposed. In the refractive index detection range of 1.333-1.385RIU, the resonance working band of channelⅠ is 627.66nm-759.78nm, with an average sensitivity of 2540.77nm/RIU, and the resonant working band of channelⅡ is 518.24nm - 658.2nm, with an average sensitivity of 2691.54nm/RIU. The processing method of S-type fiber cladding SPR sensor is simple, which effectively solves the problems of less cladding SPR sensor structure and difficult realization of dual channel. It is expected to be used in the fields of medical treatment and biological analysis.