Research On Next Generation Optical Coherent Communication Systems Based On Legacy Optical Transmission Line

With the rapid development of broadband services, especially the rapid development of wirelessnetwork based video calling applications and P2P applications so that the business operator’sbackbone network traffic continues to grow. It is more important to increase data transmissioncapacity of the existing network backbone and upgrade the existing optical fiber communicationnetwork from10G to100G optical fiber communication network. When upgrading10G opticalfiber communications network to100G optical fiber communication networks, fiber links aredifferent, optical transmitter and receiver structure have to be changed, also, the direct upgradingcost a lot. Reusing the existing10G optical fiber communication network, reducing the cost ofoptical fiber communications network upgrade appears to have a strong practical significance. Tosolve this problem, this paper proposes a hybrid model of dispersion compensation method. Datarate will achieve100G through reusing the existing10G optical domain dispersion compensationfiber link, and using the electronic dispersion compensation to compensate residual dispersion.This paper introduces the basic theory of coherent optical communication systems, including thedevelopment and characteristics of coherent optical communication systems, coherent opticalcommunication transmitter and receiver models, optical fiber transmission characteristics. Based ona typical coherent optical communication system model, the digital signal processing module of thereceiver is analyzed.Secondly, using the virtual optical instrument (VPI) constructed hybrid dispersion compensation100G coherent optical communication systems, and theoretically analyzed the mechanism ofequalization enhanced phase noise. The simulation analysis of the effects of finite impulse responseequalization algorithm enhanced phase noise shows that: equalization enhanced phase noise arepositive correlation with tap length of finite impulse response, dispersion values,and laser phasenoise. When using hybrid dispersion compensation, most of fiber dispersion is compensated by thedispersion compensation fiber, it makes hybrid dispersion compensation better than the fullelectronic compensation on resistance the effect of equalization enhanced phase noise.Finally, the paper presents three different electrical domain dispersion compensation methods toachieve the hybrid dispersion compensation, after simulation of system performance with differentelectronic dispersion compensation method. The results show that: contrasting the frequencydomain dispersion compensation algorithm, the finite impulse response has more capabilities and better stability in the residual dispersion compensation, makes it more suitable for hybrid dispersioncompensation system.