Application Of Discrete Multi-Tone Modulation For Short Distance Optical Interconnection In Data Center

Data center traffic has become the dominant source of Communication network traffic and the data center internal traffic will account for more than 70%by 2021,thus it will bring up urgent bandwidth requirements for short-distance optical communication.In the short-distance optical communication system of the data center,from the perspective of cost,the optical communication system which uses Intensity Modulation Direct Detection(IM/DD)is an ideal choice.As a special Multi-Carrier Modulation(MCM)technology,Discrete Multi-Tone(DMT)modulation technology has high bandwidth utilization and the subcarriers of DMT have orthogonality.The DMT maximizes the transmission rate by giving the modulation format and power of each subcarrier through an adaptive modulation format and dynamic bits allocation respectively.DMT technology has attracted wide attention in the field of optical fiber communication research.It can not only improve the spectrum utilization of the system,but also can effectively resist the IS I and the ICI because of the dispersion effect in optical transmission links.DMT technology is applicable to short-distance fiber-optic communications systems that are cost-constrain and is also a promising option in data centers.This thesis starts from the research value of DMT technology and builds a co-simulation system by Optisystem and MATLAB.The application of DMT in short-distance optical communication is studied,including analysis of basic system model,establishment of simulation platform and implementation of high-performance system.And the specific work is as follows:Firstly,this thesis studies the value of modulation technology represented by DMT to optical communication systems.The optical DMT system in this thesis adopts the IM/DD method,which has the advantages of low cost and low complexity and is widely used in the short-distance optical interconnects of data centers.DMT adopts key technologies such as the avoidance of bad channels,adaptive modulation formats,dynamic bits allocation,and adding the guard space.It can avoid inter-symbol interference to a certain extent and reduce the impact of noise and dispersion on the performance of system.Secondly,we realize the optical DMT system based on IM/DD.The system performance simulation of DMT is carried out at 10Gbps and 56Gbps respectively.And we analyze the impact of different rates on system performance.Finally,we studies the influence of key parameters on performance in optical DMT system,which including the influence of transmission distance,launch power and modulation type on the system.The analysis shows that in the case of large launch optical power,the nonlinear effect will become an important factor affecting the system performance.DMT has strong relative intensity noise tolerance and stronger thermal noise tolerance.