In this paper, D-type single-core fiber optic sensors and dual-core sensors based on surface plasmon resonance are devised with the purpose of comparatively exploring the characteristics of the single- and dual-core model. There is a plane that is thrown out on the surface of the fiber, and we coat this appearance with a layer of silver(Ag), rotating a cyclic distribution of air holes arranged around the PCF core's perimeter. Three strategically positioned apertures beneath the silver film create two leakage windows. This not only avoids the outward diffusion of the energy of the Y-polarised (Y-POL) core modes, but also facilitates the coupling of Y-POL core modes to the silver film via the leakage windows. In this paper, the internal structure of the optical fibre is optimised by adjusting its structural parameters through finite element analysis and observing the sensing characteristic parameters such as peak loss and half peak width. After obtaining the optimum peak, the sensitivity to refractive index and magnetic field testing is investigated. The sensor utilises the magnetic field sensitivity properties of magnetic fluids (MF) for magnetic field sensing. Our study shows that such a single-core model of the SPR-PCF sensor can bring about a magnetic field sensitivity of 110 pm/mT, while the dual-core one can reach 223 pm/mT. Fibre-optic magnetic field sensors are extensively utilized in biomedicine, environmental monitoring, engineering construction and other fields because of their characteristics of not being interfered by electromagnetic radiation, small size and high sensitivity, and they play an increasingly pivotal role in modern science and technology and engineering fields.
Zhao et al. (Fri,) studied this question.