Network operator Colt Technology Services, fibre installer Network Planning Solutions (NPS) and Relativity Networks have completed a live trial of hollow-core fibre connecting two Colt network sites in central London. Colt announced the proof of concept on 13 October 2026.
The link uses Relativity Networks’ ChronoCore hollow-core fibre and is now live within Colt’s network, according to the release. The companies did not give the length of the route, name any customers or say when the service will be sold commercially.
What is hollow-core fibre?
Ordinary optical fibre sends light through solid glass. Light travels more slowly in glass than in air, so hollow-core fibre guides it through an air-filled channel in the middle of the cable instead. The result is lower latency, the delay as data travels from one point to another.
The companies make two claims about the speed gain. Colt says ChronoCore reduces latency by around 30%. Relativity Networks says light travels roughly 47% faster in it than in conventional glass. These are the companies’ own figures; no test results were published.
Why it matters
Low latency matters most for links where milliseconds count, such as between AI data centres, between cloud regions and between financial trading sites. Colt says hollow-core fibre is likely to be used on these performance-critical routes rather than replacing ordinary fibre everywhere.
“This live central London deployment is an important step in moving HCF from technical potential into operational network infrastructure,” said Danny Preston, founder and chief executive of NPS, which installed, spliced, tested and validated the fibre.
Colt says the trial lays the foundation for future customer deployments.
What this means
- Hollow-core fibre is leaving the lab. This is a live link inside an existing city network.
- AI is a key driver. Faster links could let companies place data centres further apart.
- Details are thin. The route length, customers and launch date were not disclosed, and the speed figures are the companies’ claims.
Sources
- Colt Technology Services, “Colt, Network Planning Solutions and Relativity Networks advance next-generation connectivity with Hollow Core Fibre deployment”, 13 October 2026. https://www.colt.net/resources/insights/colt-network-planning-solutions-and-relativity-networks-advance-next-generation-connectivity-with-hollow-core-fibre-deployment
