| The sensing of magnetic field intensity and temperature has a wide range of applications in power system's partial discharge detection,composite material processing preparation,medical biological safety monitoring,etc.The sensor with functional diversity and structural integration is an effective path to realize magnetic field and temperature measurement.Compared with electrical signal modulation sensing system,optical fiber sensing system has a rapid development in recent years for its comparative advantages including high sensitivity,strong anti-electromagnetic interference,well stability and so on.Magnetic field intensity measurement and temperature measurement was combined with optical fiber sensing in this paper.A fiber-loop ring-down magnetic field and temperature sensing system based on the principle of time-division multiplexing and an all-fiber sensor for measurement of magnetic field and temperature based on Mach-Zehnder interferometer were proposed and experimentally demonstrated respectively.The detailed works include:The optical properties of magnetic sol-gel was studied,the principle of magnetic sol-gel was to realize optical fiber sensing analyzed.The preparation of magnetic sol-gel was introduced,the preparation process of magnetic sol-gel matrix Fe3O4 nanoparticles by using the method of chemical coprecipitation was described in detail,and the processing of preparation of magnetic sol-gel was also described then.The basic characteristics and sensing principle of microfiber were analyzed theoretically.The processing of microfiber preparation based on chemical etching method and oxyhydrogen flame method was introduced respectively.The magnetic sol-gel and microfiber were combined to realize the magnetic field intensity sensor head.The fiber loop ring-down sensing system based on the principle of time division multiplexing was designed and experimentally built up.The sensing system was tested,the sensitivity of magnetic field sensing system was 12.70ns/m T over a range of 25 m T-70 m T at room temperature.The temperature sensing system showed a sensitivity of 3.53ns/ ?when the magnetic field intensity was 25 m T.The sensing system exhibited both high sensitivity and stability.The all-fiber sensor of magnetic field intensity and temperature measurement based on Mach-Zehnder interferometer was proposed and experimentally demonstrated.The experiment obtained a sensitivity of 0.31nm/m T when magnetic field intensity ranging from 25 m T to 50 m T at room temperature.The temperature sensor had a sensitivity of 0.52nm/ ?over a range of 25?~30 ?with no magnetic field applied.It showed a relatively higher sensitivity.This paper provides two kinds of high sensitivity and high stability optical fiber magnetic field sensing scheme based on the theoretical research and experimental verification.It provides a reference for relevant engineering applications. |
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