STEVE ROBERTS LONG-HAUL CONNECTIVITY
BACKHAUL DEMANDS ARE BOOMING – AND THE PRESSURE TO FUTURE-PROOF DEPLOYMENTS IS ON! THE FUTURE OF FIBRE FOR LONG-HAUL CONNECTIVITY Data demand has been the one constant in an otherwise fast-changing digital landscape. Global data volumes are projected to hit 181 zettabytes by the end of 2025, fuelled by the continued rise of cloud services, streaming, hyperscale platforms, 5G, and edge computing. That is the equivalent of more than 22 terabytes for every person on Earth, writes EXA Infrastructure SVP Strategic Network Investments and Product Management, Steve Roberts .
S upporting such growth requires long-haul fibre backhaul surges alongside rapid optical innovation, operators are now facing critical decisions. With fibre expected to deliver consistent performance across a 15–25 year lifespan, which generation of infrastructure will meet future needs? networks that are scalable, high-capacity, and above all, reliable. Naturally, fibre is essential, but as demand for To find an answer, we first need to explore the current state of fibre, and consider where it is headed next.
consumption and simpler maintenance. Many G.652.D ULL fibres are also designed to meet G.657 bend-tolerant specifications, enhancing their flexibility in real-world deployments. Bend tolerance, referring to the fibre’s ability to maintain performance even when bent around tight corners, is a critical feature for routing fibre through complex urban ducts, conduits, and inside buildings. This capability not only simplifies installation in dense city environments but also future-proofs fibre assets as networks become more congested and physically constrained. G.655: BUILT FOR THE LONG HAUL While G.652.D dominates global deployments, G.655 fibre is tailored for the demands of high-capacity, long- distance transmission, especially in networks employing Dense Wavelength Division Multiplexing (DWDM). The distinctive feature of G.655 fibre lies in its non-zero dispersion characteristic. Dispersion, the spreading out of light pulses over distance, can cause signal overlap and interference, which is especially problematic in DWDM systems carrying many tightly spaced wavelengths. G.655’s carefully managed dispersion helps to minimise nonlinear effects such as four-wave mixing, which can distort and degrade signals in densely packed wavelength channels. Thanks to these properties, G.655 fibre is especially valuable for long- haul and intercity routes, where the distance between amplification points can be extensive. Operators building transnational backbones or subsea cable landings often rely on G.655 to maintain signal integrity over hundreds of kilometres, ensuring that capacity
and speed demands can be met without excessive regeneration.
TECH-READY TODAY, TESTED TOMORROW Considered together, both G.652.D ULL and G.655 fibre play a pivotal role in the current fibre landscape, providing the foundation for much of today’s long-haul and high-capacity connectivity. However, despite their strengths, there are physical constraints within these fibres that are coming to light. As global traffic surges and networks
evolve towards 400G and 800G transmission speeds, the inherent
properties of G.652.D and G.655 fibre, like the attenuation limits and dispersion profiles, pose difficult challenges. Maintaining signal integrity over longer distances with ultra-high data rates becomes increasingly difficult, forcing operators to add more regeneration sites or accept trade-offs in network efficiency. To put it simply, the fibre that has served networks so well for the last two decades is approaching the edge of its scalability. To meet future capacity demands and reduce operational complexity, new fibre technologies and architectures will need to complement or replace these legacy types, or risk creating bottlenecks that limit performance, drive up costs, and slow down innovation. THE FORCES BEHIND FIBRE’S NEXT CHAPTER Long-haul fibre infrastructure is being reshaped not only by the sheer volume of data, but by the evolving needs of those driving it. Hyperscalers, OTT giants, and large enterprises in sectors like finance, AI, and scientific research are no longer passive consumers – they are actively
G.652.D: THE GLOBAL WORKHORSE
As it currently stands, G.652.D is the most widely deployed optical fibre globally and serves as the workhorse of the optical networking ecosystem. Its versatility is one of its key strengths, supporting transmission in both the 1310 nm and 1550 nm wavelength windows, meaning that it is compatible with a broad spectrum of optical equipment. This dual-window capability allows network operators to use G.652.D in a variety of applications, from metro networks to long-haul backbone routes. The Ultra Low Loss (ULL) variant of G.652.D represents an important evolution of this standard. By reducing signal attenuation, ULL fibres enable data to travel longer distances without the need for frequent regeneration or signal boosting. This translates to reduced infrastructure costs, fewer points of failure, and improved network reliability. For operators, this means better performance with fewer active components, leading to lower energy
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| ISSUE 42 | Q3 2025
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