云计算等分布式高带宽消耗业务对下一代无源光网络(NG-PON2)提出了大容量、长距离和广覆盖的发展要求。随着NG-PON2技术的发展，无源光网络(PON)系统的光线路终端(OLT)设备结构也日益呈现出复杂化和异构等特点。导致PON 网络中出现了传统核心网中，由于链路和端口资源利用不均衡所带来的网络阻塞和带宽利用率低的问题。基于40 G 相干PON 实验系统研究了OLT设备流量均衡问题，提出了一种基于负载均担的实时监测上报告警和周期性调整相结合的动态流量均衡策略。实验结果表明所设计的动态流量均衡策略可以有效地降低PON 网络阻塞率和提高带宽利用率。

Driven by the emergence of cloud computing and high- bandwidth applications, the efforts of next generation passive optical network (NG-PON2) should be made on ultra-high capacity, long location and wide coverage. With the development of NG-PON2 technology, the structure of passive optical network (PON) system is also becoming more and more complex and heterogeneous. The traffic imbalance problem begins to appear in optical line terminal (OLT) of PON which is caused by the imbalanced utilization of link and port resources in conventional core networks. The downstream traffic balancing problem base on OLT of 40 G coherent PON system is proposed and discussed. In addition, a novel dynamic traffic balance strategy for the higher blocking probability and lower bandwidth utilization problems of 40 G coherent PON system is discussed. The experimental results show that the proposed dynamic traffic balance strategy can efficiently reduce the blocking probability and improve the bandwidth utilization.