The demodulation method of optical fiber magnetic field sensor is not expensive and practical at present.A tapered fiber mag-netic field measurement method based on fiber loop ring-down technique is proposed to realize the time domain demodulation of magnet-ic field.When the magnetic field of different intensities is applied,the loss caused by light at the tapered fiber is different,resulting in different attenuation time of the system.The relationship between the attenuation time of the system and the magnetic field intensity is established to measure the magnetic field.In order to reduce the cross-sensitivity between the temperature and the magnetic field of the sensing unit,a temperature control circuit is designed to keep the temperature of the sensor unit at 25.0 ℃.The experimental results show that when the sensor is in the magnetic field intensity range of 2 mT-9 mT,the magnetic field intensity H and decay time τ have a linear fitting degree of R2=0.98273,and the magnetic field sensitivity of the sensor is-11.65μs/mT.Compared with other demodula-ted fiber optic magnetic field sensors,the magnetic field measurement method based on fiber loop ring-down has the advantages of fast response speed,low cost and good stability.
关键词
光纤传感器/磁场测量/光纤环路衰荡/时间域解调
Key words
optical fiber sensor/magnetic field measurement/fiber loop ring-down/time domain demodulation
维普
万方数据