Dispersion Compensation In Wavelength Division Multiplexing Optical Fiber Communication System

With the advent of the information age,higher requirements have been placed on the transmission rate,channel capacity and transmission distance of optical fiber communication systems.Fiber loss,dispersion and nonlinearity are the three major factors that restrict the transmission of communication systems.The development of optical amplifiers has basically solved the problem of optical fiber loss,and the influence of dispersion and nonlinearity is an important topic in the field of optical fiber communication.In wavelength division multiplexing(WDM)systems,dispersion compensation fiber(DCF)is the most commonly used dispersion compensation technology.It has a relatively large compensation bandwidth and is easy to install,but has large insertion loss and strong nonlinear effects.And other issues.The chirped fiber bragg grating(CFBG)has the advantages of small insertion loss and low nonlinear effect.This thesis studies the dispersion compensation of wavelength division multiplexing systems based on dispersion compensation fibers and chirped fiber gratings.The main research work and results of this thesis are as follows:(1)Based on the basic principles of optical pulse transmission,the mechanism of dispersion generation is explained using the fluctuation equations of light transmission in optical fibres derived from Maxwell’s set of equations.From the dispersion classification,the effects of group velocity dispersion and higher order dispersion on the optical signal are focused on and the basic principles of dispersion compensation are explained.(2)The wavelength division multiplexing system and dispersion compensation technology are introduced,and the dispersion compensation theory of dispersion compensation fiber and chirped fiber grating is explained by deriving mathematical formulas,and their advantages and disadvantages are compared and analyzed.(3)The conventional dispersion compensation scheme based on DCF in wavelength division multiplexing systems was investigated and simulated using Opti System software to analysed the impact of the three compensation methods,namely front compensation,back compensation and symmetric compensation,on the transmission performance of the system.(4)Two dispersion compensation schemes were proposed: a dispersion compensation scheme based on CFBG+DCF and a dispersion compensation scheme based on DCF+CFBG.The simulation models and simulation parameters were calculated for the front,back and symmetrical compensation methods of the two dispersion compensation schemes respectively,and the Q value and bit error rate of different dispersion compensation schemes were analyzed and compared,and the proposed CFBG was also proved.At the same time,it was also proved that the proposed CFBG+DCF dispersion compensation scheme and the DCF+CFBG dispersion compensation scheme can optimize the dispersion compensation in the wavelength division multiplexing system,which can enable the optical fiber communication system to better achieve high quality and long distance transmission.