Implementation Of Simulation Design And Demodulation System For Ocean Temperature And Depth Dual Parametric Fiber Optic Sensor

Seawater temperature and depth(pressure)are two of the most basic parameters among many marine physical parameters.Measuring them in real time,accurately and efficiently is of great significance to marine ecological environment monitoring,seasonal climate prediction,oil and gas exploration and exploitation,deep-sea engineering construction,marine fishery investigation,navigation and navigation,and military equipment operation.At present,the traditional sensing devices for ocean temperature and depth measurement are relatively mature electrical thermometers and disposable thermometers,which have been widely used in underwater platforms such as platforms,buoys,submersibles and ships.Due to the problems of high price,weak anti-electromagnetic interference ability,high water tightness requirements,large power consumption,large size,and difficult deployment,it is difficult to meet the needs of large-scale practical applications.On the contrary,optical fiber sensors have the obvious advantages of simple structure,low cost,small size,light weight,corrosion resistance,strong anti-interference capability,high transmission rate,easy integration and multiplexing,simultaneous measurement of multiple parameters,etc.,which have gradually become a research hotspot in the field of sensing technology in recent years and have attracted wide attention of researchers in various fields.Based on this,a high-performance fiber optic sensor for integrated temperature and pressure measurement of seawater based on optical microfiber coupler is designed and developed for temperature and pressure sensing applications.The main research contents are as follows:(1)First of all,the research progress of marine temperature and pressure sensing technology is summarized,and the advantages and disadvantages of electrical and fiber optic sensors are compared.The advantages and disadvantages of optical fiber sensing structures such as fiber bragg grating type,Fabry-Perot interferometer type,surface plasmon resonance type,etc.are summarized and compared,and the problems and application prospects of different categories of fiber optic temperature and pressure sensors are analyzed.(2)An integrated fiber optic temperature and pressure measurement sensing structure based on polydimethylsiloxane encapsulated optical microfiber coupler is proposed,and the theoretical equations for the sensor output are derived by fiber optic mode coupling theory.The method of combining the MATLAB numerical calculation analyzes the impact of structural parameters on the sensor performance of the device.In addition,the best packaging structure of the device is designed using the COMSOL software simulation to achieve the optimal sensing performance.The simulation results provide design guidance and theoretical foundation for the fiber temperature pressure sensor.(3)The proposed sensor is developed,and its performance is tested and verified experimentally.The experimental results are basically consistent with the simulation results,achieving a temperature sensitivity of-2.133 nm/°C and a pressure sensitivity of 7.308 nm/Mpa.Meanwhile,the sensor also exhibits good repeatability and long-term stability,and the response time basically meets international standards.In addition,a protective housing is also designed for the device to meet the actual engineering application requirements and to improve the environmental adaptability of the sensor.(4)The Labview graphical editing language is used to design the peaktrough tracking detection program,and then the sensitivity matrix inversion operation is used to realize the dual parametric demodulation of seawater temperature and pressure.Based on the above work,the problems of poor stability,poor environmental adaptability,low linearity and demodulation difficulties faced by the tapered fiber optic sensor are not only solved,but also improved the measurement accuracy and precision of the device significantly.Overall,the sensor design will have good application and development prospects in the field of marine monitoring,and also provides a new option for seawater temperature and pressure measurement.