Looks like Infinera is prototyping 400G DWDM tranceivers.

READING, UK – Virgin Media has trialed innovative network technology which provides new ways to rollout multi-gigabit speeds to consumers and businesses.

The trial, delivered on the operator's network in Reading, saw Virgin Media install prototype Infinera XR Optics technology in its network. The new equipment plugs into the existing network and is able to send and receive data at much higher speeds than was previously possible – reaching transfer rates of up to 400Gbps in a single fibre.

In 2019, Virgin Media trialed 10Gbps symmetric full fibre home broadband technology in Papworth, Cambridgeshire. This new trial goes a step beyond that, demonstrating that the operator's passive fibre optic access network (PON) – which provides multiple premises with full fibre connections – could deliver 400Gbps symmetrical services by making use of the latest technology.

Fibre optic networks transmit data from one point to another through a series of electrical switches and optical transceivers. These optical transceivers control where the information is sent and at what speed, ultimately determining how fast data can be sent from one point to another.

In the trial, the traditional network transceivers were replaced with cutting-edge technology which split a single fibre optic cable into many connections, all taking a share of the huge capacity. This means a single fibre could be used to provide multi-gigabit speeds to many customers at the same time.

By using standard passive optical network technology, the transceivers can support higher speed data transfers and can be remotely upgraded and configured. This allows the network operator to make changes quickly and easily, paving the way for simple upgrades to consumer services in future.

This new technology could help support the rapidly growing demand for data which is being driven by high-quality video streaming, remote working and immersive entertainment, as well as the need to carry 5G traffic to and from mobile phone masts as well as other emerging bandwidth intensive technologies.

https://www.lightreading.com/opticalip/fttx/virgin-media-tests-400g-network-tech-/d/d-id/767796