Research Of Magnetic Field And Temperature Sensing In One-Dimensional Photonic Crystal

Medium-intensity magnetic field sensors are widely used in environmental magnetic field monitoring,navigation,munition detection,prospecting,traffic control,airport security,medical biology,and smart grid monitoring in recent years.One-dimensional photonic crystal sensors,which has unique photon localization and flexible design,can detect temperature or magnetic field of objects and it can provide a new idea for designing high-performance sensors due to the advantages of small size,high sensitivity and anti-electromagnetic interference.The one-dimensional photonic crystal magnetic field and temperature dual-parameter sensor which is suitable for medium-intensity magnetic field detection can not only eliminate the cross-sensitivity of magnetic field and temperature,but also the anti-interference ability and the corresponding speed can be improved relatively to the electrical sensors,so development of this optical sensor of magnetic field has practical significance and application value to the industry of magnetic field sensor.In this paper,a magneto-fluid filled one-dimensional structure which can detect magnetic field and temperature is designed.The properties of the magnetic field and temperature sensing are analyzed by finite element method with the perfectly matched layer and scattering boundary conditions.The effects of structure parameters on the magnetic field and temperature sensing characteristics have been also discussed.The period of the optimized one-dimensional photonic crystal is 7 and the thickness of defect layer is 577.58 nm.The results show that the sensitivities of the sensor can reach to 136.4 pm/m T or-34pm/? respectively when the magnetic field is from10 m T to 35 m T or temperature is from 0? to 50?,and has a good linearity in this range.As the measurement of the magnetic field is affected by the temperature,a two-parameter sensing structure of temperature and magnetic field based on defect states and optical interface state is firstly proposed.The sensing characteristics are simulated and analyzed numerically and the parameters are optimized.The results show that the magnetic field sensitivities of the sensor can reach to 156 pm/m T and 111pm/m T and the temperature sensitivities can reach-94pm/ ? and-56pm/? respectively when a magnetic field is from 10 m T to 35 m T and temperature is from 0?to 50 ? and has a good linearity in this range also.By establishing a matrix of sensitivity coefficients,the cross-sensitivity of magnetic field and temperature can be eliminated.Finally,the sensing system and the technics of the sensor are presented.The proposed new type of magneticfield and temperature sensing structure by the optical method can detect the magnetic field intensity in the magnitude of 10-4T with high sensitivity and the cross-sensitivity eliminated.