YouTube, Facebook, Skype? It all started with optical fibre trial linking Hitchin and Stevenage 40 years ago

In April 1977, scientists from Standard Telecommunications Laboratories began a technical trial to demonstrate that optical fibres – thin, flexible rods of high-quality glass – could transmit high-speed data over large distances.

This technology laid the groundwork for the infrastructure today supporting video streaming on websites such as YouTube, social networks like Facebook, and many other modern conveniences like Skype that we take for granted – with text, music, images and video transferred around the world in a split second.

Optical fibres hadn’t yet been demonstrated in a real-world environment in 1977, and the conventional wisdom was that glass couldn’t be made pure enough – but STL’s Charles Kao and George Hockham predicted as early as 1966 that they could work.

Seeking to prove the technology’s viability in the field, Harlow-based STL agreed with the Post Office to use their ducts to connect the telephone exchanges in Hitchin and Stevenage – about 5½ miles or 9km apart – and demonstrate 140 megabit-per-second transmissions.

Route of 140Mbit/second optical fibre system which carried telecom traffic between the towns of Hitchin and Stevenage, UK. The black circles indicate the location of the bidirectional regenerators in manholes. Picture: Courtesy of Standard Telecommunications Quarter Century Club (Image: Nortel)

This would be enough to carry more than 2,000 phone calls – and though it’s only slightly quicker than the superfast broadband we’re used to today, at the time it was the fastest transmission rate in the world.

Physicist Dr Bindi Bhumbra, 52 – who worked for STL some time after the trial, and moved to Hitchin in 2004 – only recently found out that his house is just a few yards from the route of the 1977 fibre optic link.

He told the Comet: “As a young physicist at the time, the work we were doing developing quantum optical components was interesting only at the technical level. I didn’t appreciate the full extent of how much impact the technology would have on our generation.

“As it turned out, because of all that development, we now have the infrastructure today that supports video streaming, mobile phone apps and social media.

Dr Bindi Bhumbra outside the exchange in Hitchin 40 years on. Photo: Courtesy of Bindi Bhumbra (Image: Archant)

“And the original technical trial that proved this could be done took place in Hitchin, only metres away from where I now live.”

The installation of the equipment began in mid-April 40 years ago, with the 9km route roughly following the A602 from Hitchin’s exchange in Hollow Lane to Stevenage’s in Exchange Road, punctuated by repeaters at 3km intervals near Little Wymondley and Coreys Mill.

The team encountered many obstacles, including flooded manholes and tight bends around which the fibre cables had to be carefully eased.

But these issues, coupled with the route’s traversing of the A1(M) and the railway line between the two towns, gave further credence to the robustness of optical fibres.

Working outside the Exchange in Hitchin's Hollow Lane in 1977. Picture: Courtesy of Standard Telecommunications Quarter Century Club (Image: Archant)

This cutting-edge communications system, put together by STL’s scientists in association with London-based Standard Telephones and Cables, turned Charles Kao’s theory into reality – and proved a pivotal moment in the history of optical communications, with Britain becoming a world leader in fibre optics development.

Today’s communication networks depend heavily on optical fibres, with undersea cables connecting the continents across thousands of miles of ocean.

And the technologies developed back then continue to be improved upon to satisfy the ever-increasing demand for higher connection speeds.

Indeed, as Bindi pointed out, it has been said that what the wheel did for road transport, the optical fibre did for telecommunications.

The Hitchin-to-Stevenage optical fibre cable being pulled into the underground ducts. Charles Sandbank and others look on. Photo: Courtesy of Standard Telecommunications Quarter Century Club (Image: Archant)

Charles Kao – now Sir Charles, and known as the ‘father of fibre optics’ – eventually received the 2009 Nobel Prize in Physics ‘for groundbreaking achievements concerning the transmission of light in fibres for optical communication’, sharing the award with American digital photography pioneers Willard Boyle and George Smith.

If all the glass fibres winding around the world were unravelled, the thread would be a billion kilometres – long enough to encircle the world more than 25,000 times, with that distance growing by thousands of kilometres every hour.

And it all started with a 9km link in our corner of the world.

A 12-minute film produced in 1977 about the Hitchin-to-Stevenage fibre optic link, Light Line, can be viewed at the top of this article or at opticalfibrehistory.co.uk/when/light-line.

David Dalgoutte aligning the optical connectors on an optical regenerator, in a footway box somewhere between Hitchin and Stevenage. Photo: Courtesy of Standard Telecommunications Quarter Century Club (Image: Archant)

To find out more about the history of fibre optics and the Hitchin-to-Stevenage trial, see the website maintained by Bindi’s former colleague Prof Richard Epworth at opticalfibrehistory.co.uk.

• We wish to thank the STL Quarter Century Club and Prof Epworth for use of the photographs and original material, and Dr Bhumbra for contribution to this article.

Optical fibre cable being installed between Hitchin and Stevenage. Photo: Courtesy of Standard Telecommunications Quarter Century Club (Image: Archant)

Installing regenerators in the watertight footway boxes. Picture: Courtesy of Standard Telecommunications Quarter Century Club (Image: Nortel)

Tony Jessop aligning the optical connectors on a regenerator at the Hitchin exchange. Photo: Courtesy of Standard Telecommunications Quarter Century Club (Image: Archant)