The 10GBASE-LX4 10 Gbit/s physical layer standard is an example of a CWDM system in which four wavelengths near 1310 nm, each carrying a 3. 125 Gbit/s data stream, are used to carry 10 Gbit/s of aggregate data. Passive CWDM is an implementation of CWDM that uses no. Use Dense Wavelength-Division Multiplexing (DWDM) SFP+ modules to integrate WDM transport directly into your Cisco 10 Gigabit Ethernet switches and routers. The Cisco 10GBASE DWDM SFP+ Modules (Figure 1) are fiber transceivers for a wide variety of Cisco switches, routers, and other equipment. Each of the channels operates at a specific wavelength in tightly packed spectral grids.