Optimization Design And Research Of Ultraweak Magnetic Field Fiber Optic Sensing System

With the continuous progress of modern science,the weak magnetic measurement technology has developed very rapidly and is widely used in many fields.With the continuous development of new theories and the continuous progress of micro/nano processing and micro system integration,miniaturization,low power consumption and high integration have gradually become the development trend of weak magnetic measurement technology.In this paper,based on atomic spin precession theory combined with high-precision optical fiber sensing technology,an optic fiber weak magnetic field sensor structure based on atomic spin is designed and the theoretical model and experimental method of the system are deeply studied and optimized.The main research contents of this paper include:Firstly,the research background and significance of the project are introduced,methods of weak magnetic measurement technology were summarized,and the research progress of atomic magnetometer at home and abroad are introduced briefly.Secondly,Studied the stability method of ultra-weak magnetic field optical fiber sensing system,constructed the structure of ultra-weak magnetic field measurement system,and established the signal output model of this structure;The high frequency alternating current heating system of the atomic gas chamber is builted,and the stability of the heating temperature is tested;The composition and stability of the pump optical path and the detection optical path are anaylyzed,and the shielding effect of the environmental magnetic field shielding device is tested;The linearity of the system signal is tested,the theoretical research and experimental test of the system polarizability are introduced.The detection principle of the system`s polarizability is Analyzed,and atomic absorption peak and polarizability are tested.Thirdly,the basic principle of weak magnetic field measurement system is introduced,and the working principle and the system structure of atomic magnetometer and the detection principle of pump light and detection light are introduced in detail,and the spin relaxation of alkali metal atomic polarization is introduced.Finally,in order to improve the sensitivity of system testing,magnetic field modulation technology is studied,the magnetic field modulation experimental system is debugged and tested,and the test results of magnetic intensity modulation are analyzed.