Research On Interferometric Optical Fiber Sensor Based On Peanut-shape Structure

Optical fiber sensor has outstanding merits which is in compact size,high sensitivity,immunity to electromagnetic interference,etc.It has been widely applied in aerospace technology,environmental monitoring,medical fields.Interferometric fiber optic sensor has high optical stability,broad responding range,working in particular surroundings such as high pressure,high temperature,highly corrosive for a long time.In recent ten years,domestic and foreign scholars focus on interferometric fiber sensor research.In the thesis,three types of fiber sensor achieved simultaneous measurement of magnetic and temperature have been proposed,which based on interferometric fiber sensor research and the relevant technology of magnetic field measurement.The sensing structure compose of the peanut-shape structure and multimode fiber,optical fiber grating,the taper structure.The main content includes:1.It sketch out the research bachground,meaning,classification and characteristics of fiber sensors.The Inline interferometric fiber sensor and the research status are introduced.2.It analyse on the sensing principle of Inline MZI and optical fiber grating.3.A magnetic field sensor based on the peanut-shape structure and multimode fiber has been proposed.It analyse on sensing principle and experimental study.It has measured on magnetic field and temperature respectively,achieved simultaneous measurement of dual-parameter based on sensitivity matrix.The MZI compose of two peanut-shape structure has two type of interference peak,one is the interference of core mode and core mode,the other is the interference of core mode and cladding mode.The experiment results demonstrates the interference peak of core mode and cladding mode sensitivity to magnetic field strength,the magnetic field sensitivity is 0.0478nm/mT.In the temperature experiment,the temperature sensitivity are 0.06nm/? and 0.0526nm/?,respectively.4.An optical fiber magnetic field sensor based on the peanut-shape structure cascading with LPFG has been proposed.It analyse on sensing principle and experimental study.When magnetic field strength change from 0mT to 20 m T,the magnetic field sensitivity of Dip1 and Dip2 are-0.064nm/mT and-0.0413nm/mT,respectively.In the temperature experiment,the temperature sensitivity of Dip1 and Dip2 are 0.2328nm/? and 0.1857nm/?,respectively.5.An optical fiber magnetic field sensor based on the peanut-shape structure and the taper structure cascading with FBG has been proposed.It analyse on sensing principle and experimental study.When magnetic field strength change from 0mT to 20 mT,the sensitivity of MZI interference peak is 0.11nm/mT.In the temperature experiment,the temperature sensitivity of MZI interference peak and FBG transmission peak are 0.4015nm/? and0.0114nm/?,respectively.