Toby Ford, Head of Operation – Comms, JSM discusses how dark fibre is transforming the UK’s digital infrastructure, offering organisations the flexibility to build secure, high-capacity networks tailored to their needs. Toby also explains how with rapid full-fibre rollout and Code Powers, JSM is helping drive this evolution – enabling faster deployment and future-proof connectivity for businesses across the country.
The rapid expansion of cloud computing, AI workloads, edge processing, and high‑density data centre interconnects (DCIs) has intensified global demand for high‑capacity optical infrastructure. Dark fibre, unlit optical fibre reserved for future use or leased to third parties, has become a critical component of modern network architecture. It enables organisations to deploy bespoke optical transmission systems, optimise latency, and scale bandwidth independently of traditional carrier services.
In the UK, the acceleration of full‑fibre rollout has created a favourable environment for dark fibre expansion. Ofcom reports that 62% of UK premises now have access to full‑fibre networks, representing 18.7 million premises and marking one of the fastest deployment trajectories in Europe. This expanding footprint provides the physical substrate required for dark fibre leasing, metropolitan fibre rings, and private optical networks.
Technical characteristics of dark fibre
Dark fibre consists of unused strands within a fibre‑optic cable, typically deployed in multi‑core bundles to future‑proof network builds.
Key technical attributes include:
Physical layer control
Users can deploy their own Dense Wavelength Division Multiplexing (DWDM) or Coherent Optical systems, enabling:
- Custom modulation formats
- Variable baud rates
- Multi‑terabit channel stacking
- Ultra‑low‑latency routing
This level of control is essential for data centres, financial trading platforms, and hyperscale cloud operators.
Scalability and future proofing
Bandwidth upgrades occur at the equipment layer rather than through civil works. As optical transceiver technology evolves, from 100G to 400G, 800G, and beyond, dark fibre capacity scales accordingly.
Security and isolation
Dark fibre provides a physically isolated transmission path, eliminating risks associated with shared carrier networks. This is particularly relevant for government, defence, and regulated industries.
Latency optimisation
Route control allows organisations to minimise fibre distance, splice count, and dispersion compensation overheads, which are critical for latency sensitive applications.
Market drivers and global context
Internationally, fibre deployment continues to accelerate. The FTTH (Fibre To The Home) Council Europe reports that over 219 million homes across Europe are now passed by fibre, with annual growth exceeding 10%. Globally, IP traffic is projected to grow at double‑digit rates driven by AI model training, 5G densification, and cloud‑native workloads.
These trends increase demand for dark fibre as organisations seek deterministic performance and long‑term cost efficiency.
JSM’s role in dark fibre deployment
With the granting of Code Powers, JSM is authorised to install electronic communications infrastructure with significantly reduced administrative constraints.
Code Powers enable:
- Street works and duct installation without individual wayleave negotiations
- Easier access to public highways and shared utilities
- Faster deployment timelines and reduced project overhead
JSM’s technical capabilities span the full deployment lifecycle:
- Route engineering and GIS‑based network planning
- Civil works including trenching, ducting, and chamber construction
- Fibre installation, splicing, OTDR testing, and commissioning
- Integration with existing utility corridors and multi‑operator environments
JSM’s experience in high‑complexity civil engineering environments positions us as a strategic delivery partner for operators, local authorities, and private network owners seeking to expand dark fibre capacity.
As the UK continues its transition toward a fibre‑first digital infrastructure, dark fibre will play an increasingly central role in enabling scalable, secure, and high‑performance networks. With Code Powers in place and extensive engineering expertise, JSM is well positioned to support national dark fibre deployment and contribute to the UK’s long‑term digital resilience.