Near-infrared double-peak PCF refractive index and magnetic field double-parameter sensing system

Abstract

The invention provides a near-infrared double-peak PCF refractive index and magnetic field double-parameter sensing system which comprises a near-infrared light source, a single-mode fiber, a sensing unit, a spectrum analyzer, a photoelectric converter, a demodulation module and a PC terminal. According to the surface plasma resonance principle, the refractive index and the magnetic field are detected through the distance between two formants of the photonic crystal fiber of a special structure, and the result is displayed in a PC end. According to the invention, a traditional wavelength sensitivity calculation method is replaced by a double-peak sensitivity formula, and the proposed novel sensing device adopts a double-peak sensitivity sensing method, and the system has the advantages of high sensitivity, flexible design, compact structure, high stability and the like, and the system has very high value in the medical field, biochemical analyte detection, water pollution monitoring and other practical use.

Description

technical field [0001] The invention belongs to the technical field of optical fiber sensing, and in particular relates to a dual-parameter sensing system based on near-infrared bimodal PCF refractive index and magnetic field. Background technique [0002] Surface plasmon resonance (SPR) exists between metal and medium (or air), and uses total reflection evanescent waves to excite surface plasmon polaritons (SPP). Due to its high sensitivity, no background interference, no sample label, no need for further purification, and real-time rapid detection, SPR sensing technology has become a multi-purpose method for monitoring the refractive index of analytes, filtering light of specific frequencies, and detecting the formation of nano-biofilms. Functional tools. In recent years, the concept of SPR sensors based on photonic crystal fibers (PCFs) has been proposed. Photonic crystal fibers are characterized by their design flexibility, so that dispersion, birefringence, nonlineari...

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Problems solved by technology

However, the PCF-SPR sensor has multiple couplings at the same time, and it is difficult and unstable to detect only the peak of one coupling mode.

Because in actual use, there is a problem that it is impossible to distinguish the confinement loss peak corresponding to the specific coupling mode and the resonance wavelength fluctuation of the confinement loss peak is unstable, resulting in undetectable problems. Guo Y et al. (Guo Y, Li J, WangX, et al. Highly sensitive sensor based on D-shaped microstructure fiber with hollow core[J]. Optics&Laser Technology, 2020, 123:105922.) proposed a double-peak detection photonic crystal fiber sensor, which detects the wavelength shift of the two peaks separately, and has two sensitivities at the same time , but there is no difference in the detection method from the above-mentioned single-peak photonic crystal fiber sensor; Xiao G et al. proposed (Xiao G, Ou Z, Yang H, et al. An Integrated Detection Based on a Multi-Parameter Plasmonic Optical Fiber Sensor[J]. Sensors,2021,21(3):803.) Double-peak detection dual-parameter photonic crystal fiber sensor detects two parameters at the same time through the loss peaks in two coupling modes, and also based on the resonance wavelength and resonance wavelength shift of the single peak. Judging the refractive index and sensitivity of the detected object, the stability is low

[0005] The above PCF-SPR sensor is essentially different from the present invention in the discrimination of the analyte state and the sensitivity calculation method, and the high-sensitivity sensor proposed at present is also limited by the performance of the OSA spectrometer, so most of the current PCF-SPR sensors only exist Based on simulation theory, the actual manufacturing effect is poor

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