The SWDM4 standard is ideal for the upgrade to 40G or 100G within a two-fiber multi-mode cabling architecture.
In simple terms, SWDM4, or SWDM, is a standards-based interface for 40G & 100G connections over a multi-mode fiber pair, rather than a MPO/MTP connection. Thus eliminating the need for more fibers or adding MPO connectivity to complete the upgrade.
SWDM4 differs from the 40G QSFP+ “Bidi” in that it is standards based. Any SWDM4 from any manufacturer will be interoperable with one another. The 40 QSFP+ “Bidi” is a proprietary protocol that is not interoperable with other manufacturers or suppliers.