Research On Key Techniques Of The Ocean Profile Pressure Measurement Based On Fiber Bragg Grating

Along with the development of Optical fiber sense technology,Fiber Bragg Grating sensor has the advantages of reuse,long distance transmission,anti-interference and high sensitivity compared with the traditional electronic sensor.It has been applied more widely in observing ocean temperature-depth profiling and mesoscale eddy.In order to realize the requirements of high density,high temporal spatial resolution and real-time continuous measurement of ocean temperature-depth profile,the key technologies of ocean profile pressure measurement that based on Fiber Bragg Grating need to be studied.The paper mainly discusses the following aspects:First,in view of the problems of low sensitivity,slow response and poor dynamic testing stability of traditional ocean pressure sensor,a towed FBG pressure sensor and a discarded double FBG pressure sensor based on metal diaphragm have been developed,which have high sensitivity,fast response and good stability.Second,On the research of temperature compensation,aiming at the problem of inconsistent response of FBG pressure and temperature compensation sensor,the cross-influence of temperature-pressure is avoided by optimizing the structure of the temperature-compensation sensor.Third,In view of the high spatial and temporal resolution requirements of the ocean section,the measurement scheme for the combination of ship load towing and full fiber temperature-depth chain is proposed,and the towed ocean profile measurement system that based on Fiber Bragg Grating is developed.Fourth,in order to achieve the engineering application target of pressure measurement system for ocean profile,the experimental calibration test and the trailing validation test are carried out respectively.Sensor's measurement performance is detected through the reference sensor: The precision of temperature compensating sensor is better than 0.01?,the precision of pressure sensor is better than 0.1%F.S.,and the correlation coefficient of pressure sensor and reference sensor ALEC-TD is as high as 0.9906.In the towing test combined with the temperature sensor,its temperature-deep profile also shows the practicality and diversity of the pressure measurement technology of marine fiber Bragg grating,having some research significance in ocean monitoring.