Research On The Mechanical Strength And Absorption Loss Characteristics Of Optical Fiber In Water Environment

Optical fiber has been widely used in sensing and communication fields because of its unique advantages.In the sensing field,compared with traditional sensors,optical fiber sensor parts have the advantages of small size,easy to carry and install,light weight,high sensitivity,strong anti-electromagnetic interference ability and so on,and more diverse application scenarios.It can play a comprehensive performance in a variety of large-scale electromechanical,petrochemical,metallurgical high pressure,strong electromagnetic interference,flammable and explosive and strong corrosion environment,to achieve effective sensing,while the price is low,it can be large-scale reuse and development.In the field of communication,optical fiber communication has become a mainstream direction of modern communication development.It has the advantages of high transmission rate,large transmission information,long transmission distance and strong transmission capacity.It has replaced the traditional cable communication in many occasions.Both fiber optic sensing and fiber optic communication will have an underwater application environment.When the fiber is in contact with the water environment for a long time,its own characteristics will be changed,which will seriously affect the working performance and service life.It is an urgent problem to study the variation of optical fiber characteristics in water environment.In this paper,the changes of mechanical strength characteristics and absorption and loss characteristics of optical fiber under water were studied as follows:This paper analyzes the water environment of optical fiber mechanical strength and absorption loss characteristics,design based on two bending method improved optical fiber mechanical strength measuring device,fiber size on the measurement results are discussed and the effect of using the formula proves the rationality of the method of measurement,has been clear about the application range of the formula,the simulation software simulation calculation is pointed out the possible error sources,using the countdown to the diameter of the fiber fracture characterization is proved the feasibility of relative mechanical strength.The experimental study of fiber mechanical strength in water environment is carried out,and the change of fiber mechanical strength in water environment is made clear.Through water bath experiment,the accelerated effect of water environment temperature on the change of fiber mechanical strength was studied,and the phenomenon of fiber surface crack growth was observed under a microscope,which verified the mechanism of fiber mechanical strength change under water environment.The absorption and loss characteristics of optical fiber in water environment were studied by high temperature water bath and high pressure hydrogen carrying experiments.It is found that the change of optical fiber absorption loss is not obvious after the high temperature water bath experiment.It is suggested that the increase of optical fiber absorption loss under water is caused by the hydrogen produced by electrolysis of water.It is found that the reversible absorption loss of optical fiber increases rapidly by hydrogen loading experiment,and the speed and amplitude of the reversible absorption loss change by changing the pressure of hydrogen loading,which seriously affects the transmission performance of optical fiber.The relationship between the absorption loss and the concentration of hydrogen in the fiber and the relationship between the diffusion coefficient of hydrogen molecules and the experimental pressure are calculated and analyzed.