One is Dense Wavelength Division Multiplexing, which uses the LAN WDM wavelength defined by 802.3, abbreviated as LWDM, which is mainly used in the 10km category of 100GBASE-LR4.
The second is coarse wavelength division multiplexing. The selected 20nm wavelength interval, abbreviated as CWDM, is mainly used in a 2km data center. We also know that the application of 100G optical modules is comparable to that of telecommunications in data centers, so the CWDM industry chain is very mature, and its wavelength selection has become a mainstream solution.
The 100G LAN WDM is classified according to the previous distance. There is no 2km file, because the LAN metropolitan area network rarely uses this distance, only the SR short distance, LR long distance, etc..., but look at the figure above, the data center The vigorous and rapid development of the 802.3 distance now adds two subdivision distances of 500 meters and 2km, DR4 and FR4, in addition to SR4 and LR4 (10km). KR, SR, CR, SR, DR, FR, LR, ER and ZR in the Y4T12 optical module
The deployment of the data center is 100 meters, 500 meters, and 2km. Although these MSA organizations are not standard organizations, the market is huge. They have developed CWDM4, 2km applications, and then added 10km indicators. Y4T209 Multi-source agreement MSA, Y2T4 100G optical module MSA-CWDM4, Y2T127 100G 10km 20km 40km long-distance optical module 4WDM MSA
