串扰对密集波分复用网络扩展性的影响

串扰是限制密集波分复用网络扩展的一个重要因素。理论分析了三种典型光交叉连接中的串扰。结果表明基于扩展贝奈斯光交换结构的光交叉连接可以完全消除低于二阶的各类串扰，同时，若将可调谐的窄带滤波器引入到结构2中可以消除低于三阶的各类串扰。用数值模拟的方法分析了带内串扰对强度调制直接检测网络扩展性的影响。结果表明，基于扩展贝奈斯光交换结构的光交叉连接对器件串扰系数的要求得到了很大的放宽，用它来组建的密集波分复用网络具有很好的扩展性。串扰多是由构成光交换节点中各种器件的非理想性造成的，通过分析得出器件中产生的串扰可以从系统中得到很好的解决。

Influence of Crosstalk on the Scalability of Dense Wavelength Division Multiplexing Networks

Crosstalk is an important limiting factor on the scalability of dense wavelength division multiplexing (DWDM) netwoks. Crosstalk contributions in three types of DWDM cross-connect topologies with dilated Benes switch architecture have been identified. Results show that first-order crosstalk can be removed in the three optical cross -connect (OXC) nodes and the second-order crosstalk can be eliminated with narrow-band tunable optical filter introduced in the second scheme. Scalability of intensity-modulation direct-detection DWDM networks which built with the three OXC nodes is compared and discussed by numerical simulation. Results indicate that dilated Benes switch-based OXC nodes have good scalability although they are built with high crosstalk-level component. Although the crosstalk of the optical devices used in OXC node is large, it can be reduced by carefully designing the OXC node topology.