Research Of Electric And Magnetic Field Sensing Based On Photonic Crystal Fiber

Photonic crystal fiber(PCF)with its uniqueness of structure and its flexibility of design,can be selective infiltrated with various of sensitive medium into the air hole to cause the change of transmission characteristics of optical fiber.So it can be designed various high sensitivity tunable devices,especially in the field of optical fiber sensing technology.The tuning characteristics of refractive index of the medium can be combined with the surface plasmon resonance effect and directional coupling effect to detect the physical parameters.Due to its advantages of anti-electromagnetic interference and assembling the sensing and transmission,PCF provides a new idea for designing the high-sensitivity electromagnetic sensing structure with important research significance and application value.In this paper,a voltage sensing structure of liquid crystal infiltrated photonic crystal fiber based on surface plasmon resonance is proposed.The sensing properties of the voltage sensor are analyzed by COMSOL Multiphysics.And then the influence of PCF structure parameters on voltage sensing characteristics is discussed.Finally,a three-layer air hole PCF structure with a single air hole plated with 40 nm gold nano-film,air hole diameter of 0.42? and air hole spacing of8?m is finally optimized.The sensing structure has a voltage sensing sensitivity up to 1.94nm/V in the low voltage range of 0~50V,and has good linearity in the range of 36 V safe voltage.On the basis,a electromagnetic double-parameter sensing structure based on surface plasmon resonance and directional coupling effect is designed in PCF.The simulation and numerical analysis of the electromagnetic sensing characteristics of the structure are carried out and the structure parameters of PCF are optimized.In the range of 90~270Oe and 5~50V,the highest magnetic field sensitivity and voltage sensitivity of 0.967nm/Oe and 2.4nm/V with good linearity degree are achieved in the electromagnetic sensing structure.In this paper,some prospective theoretical researches on electromagnetic double-parameter sensing are carried out by optical fiber optics,which has certain potential value and practical significance for electromagnetic detection,especially for the detection of electromagnetic environment around precision instruments in industrial production and the monitoring of electromagnetic radiation on the human body.