无源光网络（PON）是依赖光功率分路器达到网络资源共享的一种网络结构，是目前光接入网（OAN）的一种传输体制。与有源光网络系统（SDH、PDH）相比，重要的实现了无源光分支，设备投资少，安装简单，运行维护费用低。其特有的测距技术，增减ONU站点方便，特别适应复杂地形的需 Passive optical network (PON) is a kind of network structure that relies on optical power splitter to achieve network resource sharing. It is a transmission system of optical access network (OAN). Compared with the active optical network system (SDH, PDH), it is important to realize the passive optical branch, which requires less equipment investment, simple installation and low operation and maintenance cost. Its unique ranging technology, increase and decrease ONU site convenient, especially to adapt to the needs of complex terrain