Railway Long-distance Communication Fiber Optic Cable Performance Degradation Analysis Research

With the development of information society,the importance of communication network is not only concerned withindividuals,but also rose to the height of national information security.Railway as an important national infrastructure,the national economy of the artery and the popular means of transport,is the mainstay of the transport industry.Its security is particularly important for the country and the people.Communication optical fiber cable as the basis carrier of the railway transmission network to transmit information,played a decisive role in railway train operation safety.Ho we ver,the deterioration of transmission performance of the communication optical fiber cable has a certain degree of concealment,which poses a great threat to the safe and stable operation of railway communication transmission network.This paper mainly studies the performance degradation of fiber optic cable based on the external factors such as construction,maintenance and natural disasters,and analyzes the fiber loss in the cable according to the different dimensions of time,different terrain,different climate and different laying methods,put forwardthe fiber loss prediction algorithm,and the main work and specific research results are as follows:(1)By studying the basic structure,composition materials and performance indexes of fiber optic cable,this paper concluded that the degradation degree of fiber optic cable is mainly affected by factors such as material,natural environment and construction maintenance.And the three influencing factors were analyzed respectively.(2)The test samples are selected from four dimensions,such as different application time,different geography,different climate,different laying modes,and the test scheme and method are established based on these.This paper mainly focuses on the spot test and investigation of the optical cable samples.The basic data of the attenuation coefficient,terminal storage,the number of joints,the quality of the joint,the microbend loss,the cable injury and the polarization mode dispersion coefficient of the cable were tested in the spot.Spot researching mainly focus on the composition materials,skin,cable paste cream,coating,core changes of the cable fiber.Through the quantitative analysis and research on these factors,the paper draws these four dimensions and the influence of the external factors such as construction and maintenance on the performance degradation of the cable.(3)In this paper,a three-order smoothing optical fiber loss prediction algorithm is proposed.By comparing the prediction curve offirst smoothing,two smoothing and third smoothing,we concluded that the fiber loss value of the three smoothing index is closer to the actual loss value.The influence of the selection accuracy of the third smoothing index coefficient a on the prediction of absolute error is discussed.Finally,the simulation results show that the absolute error of the third smoothing is the smallest and the prediction result is in good agreement with the actual value,which provides an important basis for the construction and maintenance of the railway cable network.