400G QDD DR4 and 100G QSFP28 DR1 Singla Lambda Transceivers

To address the massive bandwidth demands placed on network providers, data centres are continuing their transition to faster infrastructure. 400G optical transceivers are designed to meet these high-speed connectivity demands.

400G QSFP-DD optical transceivers are available in various types - SR8, DR4, FR4, LR4, etc. QSFP-DD DR4 has a key advantage in that it is interoperable with 100G single λ optics. PMD in IEEE802.3bs clause 124 defines a DR4 that carries 400Gb/s aggregated signals over 4 fibres (PSM4). These 4 separated and independent channels carry 100Gb/s signals in PAM4 signal format over a maximum distance of 500m using single mode fibres and KP4 FEC.

The 100G DR1 in IEEE802.3cd is called 100G-single lambda and it operates at 100Gb/s PAM4 on a single wavelength. The intended use of DR1 is to interface with 400G DR4.One 400G QSFP-DD can be connected to four independent 100G QSFP-DR modules with a single breakout cable. Please note that the transceivers on the 100G side are not limited to DR1, they can be LR1 or FR1.

This interoperability between 400G and 100G allows for greater flexibility in network upgrades. If you are upgrading your network from 100G to 400G, you need a cost-effective way to connect the new equipment to what you already have in your data centre. 400G DR4 optics give you the ability to upgrade just one site with a 400G host platform and still connect it to an existing 100G site.