T&S Cex-WDM is a kind of coexistence WDM product, which is mainly used in optical fiber access network. It can use EPON/GPON network of 1 to 2.5Gbps and XG-PON network of 10Gbps rate in the same ODN. , And even use NG-PON2 network with a rate of 10 to 40Gbps; using Cex-WDM can save a lot of ODN capital investment at the access network level.