Copper vs fibre optic cable

Fibre network cables have some definite advantages over copper cables, including greater bandwidth, faster speeds longer distances, and better reliability. However, there will always be a need for copper-based solutions to make technology more affordable and applicable to the market. This article will discuss the demand for data and the barriers both fibre and copper have, defining their role in the future of the data market.

Fibre network cables have some definite advantages over copper cables, including greater bandwidth, faster speeds longer distances, and better reliability. However, there will always be a need for copper-based solutions to make technology more affordable and applicable to the market. This article will discuss the demand for data and the barriers both fibre and copper have, defining their role in the future of the data market.

The ongoing demands for bandwidth within the communications industry continue to be driven by emerging technologies such as cloud computing, IoT (Internet of Things), mobile communications, video streaming, and other on-demand services.

All of these developments involve the internet and demand high-speed reliable connections, and thus the development of optical fibre.

Data development

Transmitting large amounts of data over large distances presents a different set of challenges, from supporting a desktop computer to maintaining a wireless access point.

The internet deploys single-mode optical fibre cabling. One single-mode fibre can support 100Gb/s data transmission rates over 40 kilometers, however, achieving this performance is expensive mainly because of the discrete lasers used in the transmission hardware. Therefore, the internet remains the predominant domain for single-mode fibre.

Increasingly, internet service providers are upgrading their infrastructure, defined as the Metropolitan Network (MAN) – the link from the local exchange to the office building or home - to support fibre, single-mode, in the final stage of their network. Figure 1 is intended to illustrate the difference in the relative core, denoted by the yellow circles, diameter between single-mode and multimode fibres. The core is the area within fibre through which the signal should propagate. The diameter of the core of a single-mode fibre is 9μm or 0.009mm.

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Traditionally, small offices and homes have been serviced by copper cabling using a Digital Subscriber Line (DSL) technology. DSL enables relatively high bandwidth data to be transmitted over copper telephone cabling. They are supported early domestic internet access but remains compromised when streaming video or gaming is demanded.

The cabling structures

Local area network (LAN) optical cabling architectures, planning, installation, and testing are, like the copper cabling solutions, standardised as part of ISO/IEC 11801.

Today, LANs typically use multi-mode fibre which has a larger core and supports limited distances of up to 2 kilometers. At a 2kilometre reach, speeds of up to 100Mb/s are achievable. More typically lower gigabit protocol speeds are supported over shorter distances up to a few hundred metres.

Multimode fibre is not represented by a single product or grade. These specific grades have been optimised to support multi-gigabit applications currently deployed in LAN backbones. LAN backbone optical cabling is today supporting data rates of up to 40Gb/s over distances up to 150 metres.

In an all fibre network the final termination to a computer would require an expensive media converter. A separate media converter would be required for each computer.

Within the LAN horizontal and work area cabling environment, the architectures and application requirements challenge the concept of fibre rich or fibre to the desk installations. It is typical within a LAN architecture for the multimode fibre backbone to support data rates of up to 10Gb/s or 40Gb/s and provide the bandwidth for the distributed switch, to support 1Gb/s channels to the desktop over copper.

The technical benefits of copper-based networking technologies supporting data speeds of up to 10Gb/s and 40Gb/s are, by comparison with their optical equivalents low cost. Furthermore, the high-speed network, copper-based network switches, today support and deliver more than just data. Most 1Gb/s and 10Gb/s switches shipped today support Power over Ethernet (PoE) with the ability to supply up to 100Watts of DC power to enabled devices.

Aside from the apparent technology benefits represented by a copper Ethernet-enabled IP platform the potential environmental benefits afforded are energy and raw material resources savings. Combined, the potential environmental contribution to the climate change initiatives promoted by governments should not be underestimated. Unfortunately, optical fibre cabling cannot accommodate these environments

The IEEE together with its global industry members has identified the need for a simplier, smaller, lighter weight copper cabling solutions which would also deliver power over an extended copper cabling network. In 2019, the IEEE published IEEE 802.3cg which sets the standard for single pair ethernet (SPE) which is capable of supporting data rates up to 1GB/s and other protocols over distances up to 1000 metres. SPE can be powered. While developing IEEE 802.3cg the organisation also introduced and standardised the technology for Power over Data Line (PoDL), which can deliver 50Watts of DC power to enabled devices.

IoT, IIoT – industrial applications, PoE, PoDL or the needs of the building automation, industrial automation and controls or process automation industries, however, do not spell the end for optical fibre cabling.

Data centre requirements

Cloud computing and the infrastructure for the supporting data centres are fibre rich. Within the data centre environment high speed, low latency links are essential. These links are best served by fibre, even though many of the links may be short. Furthermore, data speeds in a data centre are increasingly moving towards transmission rates of 100Gb/s and 200Gb/s, which is currently beyond the capability of established traditional four-pair copper cabling.

Beyond the ability to move large amounts of data fast, a major consideration for the designers and owners of data centres is energy consumption. Large concentrations of computer processing power, servers, and storage devices generate heat. Elevated temperatures do not represent the most ideal running conditions for this equipment, therefore substantial investment is required to supply cooling to maintain optimal climatic conditions within the data centre.

Those familiar with Category 8 copper cabling will be familiar with the restricted 30 metre reach of the solution. This restricted reach was substantially influenced by the power budget imposed by the physical layer interface (PHY) engineers during the development of the 40GBASE-T solution within IEEE. The IEEE working group recognised the cost of energy and the commercial implications around over-engineering a technology.

Optical PHY’s consume much less energy than their copper equivalents. Early studies concluded that copper-based 10GBASE-T PHYs consumed around 8 Watts per user compared with the equivalent optical 10G-SR PHY consuming less than 1 Watt. The increasing deployment of optical high-speed interconnects within data centres will only help to drive the significant operating costs of energy down.

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Fibre optic cable within a data centre

What are the future application requirements?

Technology is arguably converging. Businesses and individuals across most of the globe have high-speed access to the internet data collected on a sensor in the office, factory floor or from a motor vehicle is available immediately in the cloud.

Powering your laptop, PC, TV or adjusting your office lighting or temperature through your mobile phone are, or will soon be, reality and this is largely down to IP and the ubiquitous Ethernet platform. Supporting these technological advances, communications cabling has evolved significantly since the original development of Ethernet in 1978. This evolution continues to develop at a pace, as the boundaries of technology are pushed from multiple directions.

At the core of the internet, cloud computing represents the most efficient solution for businesses and consumers alike. Efficiencies are maintained through access to improved and maintained software platforms. Secure and reliable infrastructure delivers readily available information. Cloud computing and the data centre infrastructure, which underpins the need for high-speed data transportation will continue to be serviced by optical fibre technologies.

Standards bodies are already considering the development of Terabyte speed networks to support the demands of tomorrow and challenge the current fibre technology. Increasingly, decisions surrounding technological advances are correctly informed due to the environmental impact of future developments and their energy efficiency.

Looking towards the edge of the network, IoT and IIoT continue to drive and challenge the thinking around applications, traditional protocols and energy efficiency. The demand to drive improvements in how buildings or factories are designed and used will also drive new requirements.

Creating more productive and effective environments where sensing technologies are used to collect data and collect data analytics, which informs the user of improved ways to control and manage key processes.

At this level, copper cabling, complemented by a wireless overlay structure, provides the most efficient technology solution.

The role of third-party testing

Most manufacturers undertake rigorous product development programmes to meet or anticipate the developing needs of the market. A constant challenge remains. Inevitably the speed of a market’s progress proceeds the global standards-making processes. It remains a truism that standards help regulate or control an established market, but standards do not necessarily establish or precede a market.

An independent, third-party testing and certification organisation is best placed to provide an impartial assessment of products before they are taken to market providing an additional level of confidence to the manufacture and a degree of assurance to the end-user of ongoing cable product quality.

For more information about the role of data cable for the end user download the BASEC data communication guide.

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