Compared with ordinary optical modules, the biggest difference is WDM optical module can save fiber resources and costs.
At present, the commonly used 25G WDM optical modules are divided into 25G CWDM, 25G DWDM and 25G LWDM optical modules.
25G CWDM optical module uses CWDM DML lasers and PIN/APD receivers. The working wavelength ranges from 1271-1371nm, 1471-1571nm, with each interval of 20nm, and the maximum transmission rate is up to 25.78Gbps. The transmission distance can reach 10km-40km through single-mode optical fiber connection, which can be applied to short-distance data transmission in 25G Ethernet switches, routers, network interface cards and storage network equipment.
25G DWDM is hot-swappable optical module which uses DWDM technology, the working wavelength is 1528.77nm-1563.86nm, with interval of 0.8nm, a total of forty-four channels can be selected, and the maximum transmission distance through single-mode fiber is up to 10km, widely used in 25G Ethernet and 5G fronthaul CPRI/eCPRI networks.
25G LWDM optical module uses LWDM technology. It ranges from 1269.23nm to 1318.35nm. There are 12 channels with an interval of 4nm of each channel. It can transmit as long as 40km when connected to a single-mode optical fiber, applied to 25G Ethernet medium and short distance transmission.