Research On Signal Detection Technology Of Optical Fiber Weak Magnetic Sensor

As an effective method for studying the properties of matter and detecting the unknown world,weak magnetic detection has been widely used in various fields.But in recent years,along with the advance of the times and the rapid development of technology,people have put forward higher requirements on the sensitivity and size structure of magnetic field sensors.How to improve the sensitivity of magnetic field sensors and reduce the size of magnetic field sensors has become a research in the field of magnetic fields in various countries.Hot spot.However,under the premise of ensuring the normal operation of the magnetic field sensor,how to extract the weak signal from the noise is of extremely important research value.In the traditional magnetic field detection,the extraction of weak signals mainly adopts the double-beam method,which undoubtedly increases the size of the system structure and reduces the sensitivity of the system.This paper adopts a single beam scheme for measurement,and uses the structure of the atomic magnetometer to change the principle of signal detection,which has a very important reference value for the study of micro-structured magnetic field sensors.The main research contents are as follows:1?The working principle of the atomic magnetometer was studied.Mainly taking rubidium atoms as examples,the fine and hyperfine structures of rubidium atoms are discussed separately,the pumping action of rubidium atoms under the action of pump light and the polarization under the action of external magnetic field are studied,and the properties of rubidium atoms are analyzed.Three relaxation mechanisms.2?The design and simulation of three-dimensional magnetic field coils are carried out.Mainly designed the (?)80×260mm~3 size frame and the (?)19×80mm~3 size frame of the three-dimensional degaussing coil.Based on the theory,the mathematical model of the three-dimensional magnetic field coil is established and solved,and the energy generating The size of the coil structure with the largest uniform magnetic field is verified by simulation and experiment to verify the rationality and feasibility of the coil design.From the perspective of compensating for the residual magnetic field,the sensitivity of the system is further improved.3?The weak signal was extracted.By analyzing the interaction between the magnetic field signal and the rubidium atom,the relationship between the rubidium atom and the external magnetic field is obtained.Based on this relationship,a specific modulation signal is provided to the magnetic field signal.Absorption curve and dispersion curve.On this basis,the calibration method of the sensitivity of the magnetic field sensor is given,and the sensitivity of the system is further improved by optimizing the light source and modulation parameters.4?The whole experimental system is studied.According to the results of the experiment,the main factors affecting the sensitivity are further put forward,including the degree of circular polarization of the light source,the temperature of the rubidium atomic gas cell,and the drift of the laser frequency.These factors are analyzed in detail through experiments.