Tapered-arc optical fiber SPR refractive index sensor with low structural-parameter dependence

Abstract Minor variations in structural parameters can severely compromise the performance of optical fiber sensors, thereby increasing fabrication complexity. This paper proposes a tapered-arc structured surface plasmon resonance (SPR) sensor based on plastic optical fiber (POF). The sensor’s simple fabrication process is complemented by its insensitivity to variations in structural parameters. Within the external refractive index (RI) range of 1.333–1.383, the resonance wavelength shift coefficient for sensors with different structural parameters remains below 0.872% at the same environmental RI. Its sensing performance exhibits minimal sensitivity to variations in structural parameters, thus confirming its low structural-parameter dependence. This characteristic significantly reduces the fabrication difficulty of the fiber sensor. Compared with similar POF-SPR sensors, the proposed sensor achieves higher RI sensitivity, reaching 1938.286 nm/RIU. These findings provide valuable insights for the practical application of POF-SPR sensors.