From Copper to Fibre: The UK's Telecom Network Evolution

After more than one hundred years of copper cables being used in telecommunications, BT has finally announced that no new copper cables will be installed in favour of optic fibre systems. The transition from copper to fibre optics is not just a technological advancement but also a reflection of the evolving needs of our digital society. With the increasing demand for high-speed internet and reliable communication systems, the limitations of copper cables have become more evident. Openreach's announcement to retire the copper network is a significant step towards embracing a more efficient and future-ready infrastructure.

In this article, we ask, what advantages does fiber optics have over copper, what did BT exactly announce, and why are fibre optic systems future-proof? 

What advantages does fibre optics have over copper cables?

Copper cables have been the foundation of electronics since the development of the first circuits, thanks to its high conductivity, malleability, and excellent thermal characteristics. Copper is also easy to solder, which makes it ideal for use in printed circuit boards, and its ease of mining and processing makes it an excellent option for large-volume production. 

While copper is unlikely to ever be phased out of electrical distribution, its use as a conduit is being routinely challenged by another technology: fibre optics. When sending data down copper wires (such as phone conversations, internet traffic, and sensory data), engineers face numerous challenges relating to bandwidth, interference, and signal degradation, and all of these factors arise due to the physical properties of copper cables.

On the flip side, fibre optic cables (which utilise light) offer engineers substantially larger bandwidths, allow for multiple data channels down a single cable (as photons of different frequencies do not interfere with each other), and can even be used bi-directionally at the same time. Furthermore, fibre optic cables are generally smaller and lighter, allowing for more to be bundled in the same space as copper cables.

Another major advantage to fibre optic cables is that they do not interfere with other nearby cables, nor are they able to be interfered with. This not only makes them great for high-density installations but also makes man-in-the-middle attacks nearly impossible without having to splice a cable and insert a physical junction.

However, one common misconception regarding fibre optic systems is that they provide greater bandwidth due to the speed of light, but this is entirely false as the speed of light in fibre optic cables is slower than the speed of an electric pulse in a copper cable (this makes signal latency in copper cables lower).  

According to a report from the UK government, telecommunications networks are a vital part of the Critical National Infrastructure. The shift to fibre optics ensures that the UK's communication backbone remains robust, secure, and capable of handling future technological advancements.[source]

BT announces a move away from copper cables

Despite being the foundation of telephone networks, BT has recently announced that it is finally halting all new copper cable installations in favour of fibre optic cables. The move to drop copper comes down to the future-proof nature of fibre optic cables and the ongoing modernisation of the OpenReach network, which is able to provide customers with bandwidths of up to 1gbps. 

"Our new Ultrafast Full Fibre network connects homes and businesses across the UK directly to our exchanges with a single pure fibre cable. It will give speeds up to 10x faster than current technologies, have 70-80% fewer faults than our current technology that relies on a mix of fibre cables and copper cables leaving you with no more buffering or downtime, and future proof the nation for decades to come. We now send as much data every 10 minutes over the internet that was produced from the beginning of time to 2003 and it’s only increasing – so we need a network that can cope."

This announcement from BT, however, comes as no surprise due to prior announcements by BT back in 2017 mentioning how their older Public Switched Telephone Network (PSTN) will be replaced with an entirely digital system. This means that calls will no longer be transmitted as analogue signals down copper lines but instead as data streams from telephones (essentially making connected house phones VOIP systems). 

With the new announcement, customers who sign up for new contracts will be placed onto the new network. Customers are also able to switch to the new system whenever they want, and BT encourages all customers to make this switch. If customers do not make the switch by 2025, it is possible for phone systems to cease working.

Why are fibre optic systems future-proof?

One unusual fact regarding fibre optic cables is that the limitations they face generally have nothing to do with the cable itself but the equipment used to send pulses of light and decode these pulses. This fact was demonstrated by researchers who were able to send the equivalent of all global internet traffic through a single fibre optic cable.

If this demonstration can be done on any existing fibre optic cable installation, it goes without saying that they will remain useful for centuries to come. Considering that it is highly unlikely for individual homes in the far future to be sending data at speeds exceeding 250Tbps, current installations of fibre optic cables will unlikely ever reach their physical limits.

Additionally, it should also be considered that because photons of different wavelengths do not interfere with each other, it is theoretically possible to have thousands of individual channels using a single optic cable, with each channel being a specific frequency of light. Thus, whenever a single channel becomes full, another frequency of light can be used, instantly adding a massive amount of additional bandwidth. 

Copper cables have been fantastic in analogue and digital networks, but now that technologies such as fibre optic cables are becoming dominant, it’s time for copper to retire. 

In conclusion, as we usher in a new era of digital communication, it's essential to adapt and adopt technologies that not only meet the current demands but are also equipped to handle future challenges. Fibre optics, with its myriad advantages over traditional copper cables, is undoubtedly the future of telecommunications.