Research On Optical Fiber Current Sensing Based On Magnetic Fluid

Magnetic fluid is a novel functional nano-materials, which has very unique physical properties and optical properties, and has been widely used in the electrical,mechanical, medical and many other fields. In the field of external magnetic field, the magnetic fluid exhibits unique optical transmission characteristics, which is playing an increasingly important role in the field of optical fiber current and magnetic field sensing. Therefore, it is very important to study the optical transmission characteristics of magnetic fluid under the influence of external magnetic field. In this paper, the structure of optical fiber current sensing based on magnetic fluid is prepared, and then the optical transmission characteristics of the sensing structure under the influence of external magnetic field are studied.In this paper, the optical transmission characteristics of the magnetic fluid are analyzed theoretically, at the same time, the influence of the magnetic fluid film thickness, the external magnetic field and ambient temperature on the optical transmission of the magnetic fluid film is studied. Optical fiber current sensing structure is designed and fabricated by the use of the structure of optical fiber end face,meanwhile, a magnetic fluid film is formed between the two fiber end surfaces, and then sealed. The experiment measures the relationship between the optical transmittance of the sensing structure and the variation of the magnetic field, which including the measurement of the relationship curves of the optical transmittance and the variation of the magnetic field with different magnetic fluid film thickness or different ambient temperature, and the results are analyzed. A dual light path method is proposed to study the optical transmission characteristics of the prepared sensing structure, and this method avoids the influence of fluctuation of the light source and the environment temperature on the accuracy of the measurement results. This article measures the optical transmission characteristics of the prepared sensing structure in the AC magnetic field by the method of dual light path, obtaining the variation curves of the optical transmission power ratio and the current intensity.This paper studies the optical transmission characteristics of the structure of optical fiber current sensing based on magnetic fluid from two aspects of theoretical analysis and experimental measurement, which lays a solid foundation for further application in practice.