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London, UK 22nd January 2026 - Colt Technology Services (Colt), the global digital infrastructure company, today announced a Multi-Core Fibre trial across its London metro optical production network. The pilot marks a breakthrough in next generation optical transport and makes Colt one of the first providers worldwide to test and validate the technology.
Multi-Core Fibre is a type of optical fibre that can carry several light signals (or data streams) at the same time, boosting bandwidth without adding extra cables. The trial compared its performance and scalability with traditional Single-Mode Fibre, which only carries one light signal. During the trial Colt worked with partners including Sterlite Technologies Limited (STL), Ciena and Nokia. Multi-Core Fibre is a type of optical fibre that can carry several light signals (or data streams) at the same time, boosting bandwidth without adding extra cables. The trial compared its performance and scalability with traditional Single-Mode Fibre, which only carries one light signal.
During the trial Colt worked with partners including Sterlite Technologies Limited (STL), Ciena and Nokia.
Multi-Core Fibre technology is designed to meet the surge in data traffic generated by AI, cloud computing and streaming, making it ideal for content providers and hyperscalers looking to grow capacity while scaling back deployment costs. It also supports organisations looking for smarter ways to address the increase in emissions generated by AI traffic, by expanding the capacity of existing infrastructure and reducing reliance on new power-intensive technologies.
Buddy Bayer, Chief Operating Officer, Colt Technology Services, said:
“As demand for network capacity surges, customers need more bandwidth without compromising security, performance, or sustainability. At Colt, we’re pushing the boundaries of optical networking, and this pilot marks another breakthrough. It demonstrates our commitment to delivering future-ready, sustainable networks that meet growing needs without costing the earth.”
Rahul Puri, CEO, Optical Networking Business, STL, commented:
“Innovation is at the core of how STL builds the networks of tomorrow. Our R&D teams, together with our customers, are pushing the boundaries of optical technology to bring advanced solutions like Multi-Core Fibre from the lab to field deployments. STL’s Multiverse Multi-Core Fibre is a result of this deep R&D commitment — designed to unlock massive capacity, enhance security, and deliver truly future-ready networks. We are proud to partner with Colt and co-create the next era of optical infrastructure that will power AI, cloud, and next-generation digital applications globally.”
Notes to Editors
Single-Mode Fibre is the traditional technology commonly used within optical networks, subsea cables and backbone infrastructure. It’s ideal for long-distance, high-speed data transmission, with a single mode of light travelling through the core, reducing signal loss and distortion. By comparison, Multi-Core Fibre has multiple cores in one fibre, which allows for parallel data transmission, significantly increasing bandwidth without the need for more cables.
Multi-Core Fibre:
- Saves physical space in ducts by reducing the need for additional cables
- Reduces the total cost of ownership, with fewer cables and reduced maintenance costs
- Improves sustainability
- Supports future networking requirements needed for AI and quantum computing
- Simplifies organisations’ digital infrastructure by reducing the cost and complexity of managing and monitoring multiple cables
The trial was conducted within the London Metro network between two Colt PoPs, covering distances of approximately 9 km and 63 km. An 800 Gbps line rate was achieved using Ciena and Nokia technologies, with validation performed for 100GE and 400GE services. Comprehensive testing was carried out, including Chromatic Dispersion (CD),Polarization Mode Dispersion (PMD), Crosstalk, Throughput, Fault analysis, OTDR, Loss, and Optical Return Loss (ORL) measurements, all of which delivered satisfactory results.
STL is among the first companies to demonstrate field deployments of MCF technology, spanning underground and duct networks with a complete ecosystem of fibres, cables and termination solutions.
