摘要
The tremendous and consistent increase in the volume and heterogeneity of traffic has resulted in major innovations in the telecommunication networks.In regard to the optical networks,existing studies have shown that by adopting a mixed line rate(MLR)strategy,the wavelength division multiplexed optical networks can cost-effectively respond to the diverse variety of traffic requirements which have heterogeneous service demands.Unlike existing studies which focus on various MLR network issues by considering deployment of the standard single mode fiber only within the network,in the current work,we investigate the signal quality deterioration due to the combined effects of dominant physical layer impairments for an MLR optical network conforming to the various ITU-T compliant fibers and also considering the optical frequency grid based on ITU-T Recommendation G.692.The main aim of our current study is to identify,for a given fiber,the modulation format configuration which provides the highest performance.We conduct extensive simulations on the considered MLR system using the obtained optimum channel spacing values between the single and mixed line rates.Our results show that the existence of 10 Gbit/s line rate has a detrimental effect on the 40 Gbit/s and/or 100 Gbit/s line rate;however,the 40 Gbit/s and/or 100 Gbit/s line rate’s effect on a 10 Gbit/s line rate is not so detrimental,as well as between the similar line rates.Overall,our results clearly show that choice of the line rate of both,the central channel and its adjacent channels,has a major effect on the MLR network performance.
