Research On Quasi-distributed Marine Oil Spill Detection Technology For Long-period Fiber Gratings

Marine oil spill caused a huge waste of resources at the same time also seriously endanger the marine ecosystem and human health.Therefore,It is very important to realize the rapid and accurate detection of marine oil spill.Long-period fiber gratings have a high sensitivity to the changes of external environment and have been widely used in the field of communications and sensing.Based on its refractive index sensitivity,this paper presents the influence of the external refractive index change on the transmission spectrum of long-period fiber gratings emphatically and proposes a quasi-distributed oil spill detection system based on long period fiber grating;Also the paper studies temperature-sensitive characteristics of long-period fiber gratings and eliminates the effect of temperature on the system detection results by introducing the reference grating method.The main content is included as follows:Firstly,the development of marine oil spill monitoring technology and fiber grating are introduced and the influence of external environment on the resonant wavelength of long-period fiber grating is analyzed emphatically based on theoretical aspect for the experiment.Secondly,the grating spectral properties of pure oil,water with oil,solution mixed diesel and kerosene are detected by Long Period Fiber Grating and the relationship between resonant wavelength,transmission loss and diesel concentration was analyzed,then grating was corroded by hydrofluoric acid to improve its refractive index sensitivity and to detect the effect of a small amount of oil spills.Thirdly,a quasi-distributed sensor network with long-period fiber grating is proposed to detect the marine oil spill.The demodulation part of the quasi-distributed detection system is carried out.The oil spill detection test is carried out to verify that the system is used for marine oil spill detection feasibility.Finally,the influence of the resonant wavelength of the long period fibergrating is analyzed and the effect of temperature on the test results was analyzed by experiment,then chooses the method of adding the reference grating to reduces the impact of temperature on the system.