Future-proofing the internet through fibre optic innovation
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The COVID-19 crisis has seen people all over the world rapidly moving their work and social lives online; we have never relied on the internet more. But did you know that the fibre optic network that supports today’s internet was made possible by ground-breaking research at the Optoelectronics Research Centre (ORC) at the University of Southampton?
Professor David Richardson, Co-Investigator of The Future Photonics Hub talks about the ORC’s heritage as a pioneering centre for optical fibre discovery, and describes how the research programme is continuing to investigate revolutionary new technologies for a faster, higher-capacity internet to meet future demand.
When did photonics research at the ORC begin?
The ORC recognised the potential power of photonic technology very early on. Research began here in the early 1960s, led by Professor Alec Gambling, who in 1964 presented a paper to the British Association for the Advancement of Science suggesting that optical fibres could be used for high-speed communications. At around the same time Charles Kao, known as ‘the father of fibre optics’, was exploring the potential of this technology at the Standard Telecommunication Laboratories in Essex.
What were the first optical fibre innovations to come out of the ORC?
In the early days efforts were focused on developing the technology to fabricate fibres. One of the group’s PhD students, the now renowned Professor Sir David Payne, was behind the design and construction of the first ORC fibre-drawing tower.
Another key research goal was to lower the rate of attenuation (the rate at which a light beam loses intensity as it travels through a fibre – also known as loss) to enable data to be transmitted over longer distances. Our researchers played a seminal role in this during the 1970s by developing a vapour deposition technique to produce the high-purity glass needed in the central core of the fibre. The ORC held the record for the minimum loss in a fibre in the early phases of the technology, before it was taken up by large corporations who ultimately pushed it down to today’s levels.
Identifying fibre designs with low dispersion – a measure of the distortion of a signal as it travels through a fibre – was another early achievement, along with the development of fibre fabrication techniques that are now routinely used to eliminate a form of dispersion known as polarisation mode dispersion.
Were there any breakthroughs beyond the design of the fibres themselves?
A revolutionary piece of enabling technology, the erbium-doped fibre amplifier, was invented here in the late 1980s by Professor Sir David Payne. At that time, fibres were capable of transmitting over distances of around 100 kilometres, but the technology relied on electronic devices called repeaters to boost signals so they could continue to travel for the next 100 kilometres. This involved electronically detecting the incoming signal, recovering the data, and encoding it onto another light beam to travel through the next 100 kilometres of fibre, and so on, which slowed down the system. What the world was looking for was a device that would boost signals optically, without the need to convert them using electronics – and Southampton provided it in the form of the fibre amplifier.
It works using a process called stimulated emission, in which erbium ions in the core of the optical fibre are excited by light from a laser diode, providing a reservoir of energy that is used to boost the power of the flagging signal. Importantly, one optical amplifier could simultaneously amplify signals on different wavelengths travelling through a single fibre, whereas with electrical repeaters you would need one repeater to deal with each different wavelength.
How have these developments contributed to the internet we’re using now?
We always knew optical fibres had intrinsic transmission capacity, but even 20 years ago the idea of everyone being able to do real-time video conferencing over the internet, for example, was a dream. Innovations in fibre and amplifier technology at Southampton have played a major part in making it possible, and they continue to underpin today’s fibre optic network.
So why does fibre optic communications technology need a rethink?
The transmission capacity of optical fibre is so large that we never thought we’d reach the point where we were beginning to use it all up. But in the last five to 10 years we’ve realised that we’re now close to doing just that. Until now, making improvements to the current technology has been a very cost-effective way of scaling up the bandwidth. However, the current systems are now pretty much optimised. Increasing capacity would mean putting more and more of the existing cables into the ground, which would in turn drive up costs in an ultimately unsustainable way.
A faster, more reliable internet with larger bandwidth will also enable developments in all sorts of areas, such as 3D video conferencing and virtual reality. Perhaps in future we’ll all be having meetings in exotic virtual locations rather than in our offices.
What avenues are Future Photonics Hub researchers pursuing to find solutions?
We’re working on delivering the next generation of internet that will be even more powerful, more reliable, more responsive, and have a higher capacity.
The design of the fibre that is used today, known as the single mode fibre, has been basically the same for the last 30 years. It’s time to look at that fibre and ask ourselves whether there is a better solution. We’re investigating ways to use the physical real estate within the fibre more effectively and increase the performance of the associated components such as amplifiers.
Tell us about the innovative fibre designs you are exploring.
We’re developing hollow core fibres, a visionary technology that we have been working on in the Optoelectronics Research Centre for about 15 years, the last 10 with ever-increasing focus. A conventional single mode fibre is solid; the central core through which light travels is made of high-purity glass. In a hollow core fibre, as the name suggests, light travels along a hollow core in the centre of the fibre. This allows light to travel 50 per cent faster, reducing the delay inherent in today’s internet. It is also ultimately predicted to offer lower loss than current technology, which could be hugely enabling for high capacity systems.
The hollow core fibre is very futuristic and in the short-term will be used for more specialist communications applications, but ultimately our hope is that it will become cost effective and much more widely deployed in our global networks.
How will these innovations ultimately have impact in the wider world?
We will seek to commercialise the most promising work, continuing the ORC’s long heritage of successfully spinning out companies. SPI Lasers, which was spun out in 2000, is one such success story – it originally focused on fibre optics for the telecoms sector and now produces high-power lasers for manufacturing. Another is Fibrecore, which dates back to the mid 1980s and is now the world’s leading manufacturer of speciality fibres. More recently, a company called Lumenisity was spun out to commercialise hollow core fibre technology.
As well as forming spin-outs, we have a track record of working with industry to test our new technological developments in the field, and some of the world’s biggest companies are investing in us to develop their next generation products. The ORC has worked with global telecoms companies such as NTT and Nokia, and Airguide itself has 24 project partners, ranging from Microsoft, BT through to component manufacturers and companies in the healthcare and aerospace sectors. We’re investigating a broad range of applications and The Future Photonics Hub is the interface we work through to commercialise or transfer technologies.