New BT tech between Dublin and London clocks 400Gbps speeds in world first

24 Jul 2019

Image: © alexskopje/

Using new technology, BT Ireland and its wider group have clocked speeds of 400Gbps over ethernet between Dublin and London.

In a bid to future-proof demand for higher internet speeds for business and personal use, BT Ireland, in conjunction with the wider BT group, announced a successful and significant trial on its international network.

In a statement, the telecoms company said it achieved 400Gbps ethernet speeds between Dublin and London – across 1,454km of looped cable – using a new technique called probabilistic constellation shaping (PCS).

At such speeds, a person would be able to download 50 hour-long episodes of TV in one second, or download 16,000 video streams simultaneously. Involving the manipulation of light waves to increase overall performance, the combination of 400Gbps and PCS is, BT Ireland said, a world first that would allow carriers to drive signals further along the network at higher bandwidth rates.

It added that the trial marked the longest real-world demonstration of this technology in the world to date. With this trial marked as a success, BT Ireland said it will pave the way for full commercial deployment on the network between Dublin and London later this year.

‘Challenging trial’

Dr Katie Brown, director of connectivity at BT Technology, said: “Continued traffic growth places huge demands on our underlying optical fibre transmission infrastructure. It is therefore critical that we drive and exploit innovative technology solutions that allow us to deliver increased speeds and fibre optic capacities cost-effectively.

“I am extremely proud of these achievements, especially the pragmatic and seamless deployment of these new technologies to support emerging and future high-speed services.”

Meanwhile, BT Ireland’s head of network design and core capacity, Paul Hackett, added: “It was a challenging trial, involving an extensive distance using a subsea fibre plan, but the results have been very successful and we’ll be ready for the early adopters of this technology once the industry catches up with the innovation.”

Colm Gorey was a senior journalist with Silicon Republic