What Is SWDM4?

To begin with, you should know what the SWDM is before knowing anything about SWDM4, right? Then, what is SWDM?

Actually, SWDM, whose whole full name is short wavelength division multiplex, is a new multi-vendor technology that promises to provide the lowest total cost solution for enterprise data centers upgrading to 40G and 100G Ethernet with the existing 10G duplex OM3/OM4 MMF infrastructure. What’s more, it can cost-effectively increase bandwidth density for new data center builds and extend the reach when used with OM5 wideband multimode fiber (WBMMF) as well. By the way, OM5 fiber also future-proofs the infrastructure for possible future 200G, 400G and 800G interfaces.

To upgrade data centers to 40G/100G Ethernet without changing the existing duplex MMF infrastructure being used for 10G Ethernet, pluggable optical transceivers with SWDM technology matters a lot. This approach consists of multiple vertical-cavity surface-emitting lasers (VCSELs) operating at different wavelengths in the 850nm window (where MMF is optimized). The four-wavelength implementation of SWDM is called SWDM4, and these four wavelengths (850, 880, 910 and 940 nm) are multiplexed/demultiplexed inside a transceiver module into a pair of MMFs (one fiber in each direction, i.e., a standard duplex interface). Each of the four wavelengths operates at either 10G or 25G, enabling the transmission of 40G (4 x 10G) or 100G (4 x 25G) Ethernet over existing duplex MMF, using standard LC connectors.