Research On Sampling Clock Synchronization Techniques Of Real-Time IM/DD Optical OFDM System

With the rapid development of global Internet,IP traffic in the backbone network doubles every two years,which greatly challenges the network's transmission capability.Optical OFDM(OOFDM)technologies are proposed in that case,using OFDM in optical communication systems increases not only transmission capacity but also configuration flexibility.Intensity Modulation/Direct Detection(IM/DD)are common sending and receiving techniques used in conventional optical communication systems,with advantages of easy to implement and low cost.However,owing to the thermal noise and limit of crystal oscillator's accuracy,the independently running clocks in transceivers of real-time IM/DD OFDM systems lead to sampling clock offset(SCO)between transmitter and receiver,which seriously degrades transmission performance.To solve the problem,the thesis does theoretical analyses and simulations in detail,and finally implements a sampling clock synchronization schema suitable for optical IM/DD-OFDM systems.The main achievements and innovations of the thesis include:(1)A MATLAB simulation platform is developed to verify the damage mechanism of SCO to optical IM/DD-OFDM system.(2)A pilot based frequency incrementally adjusting sampling clock synchronization technique is proposed and theoretically analyzed.(3)A real-time optical IM/DD-OFDM transmission system is built,and the sampling clock synchronization schema is implemented,which is demonstrated to be a high performance solution.