How Underwater Cables Power The Internet Across The Atlantic

Diver checking a submarine cable - Safiqur Rahaman Safiq

Nearly all of the data sent between continents goes through fiber optic cables that reside at the bottom of the ocean. It's a delicate and costly, but essential, network for our daily lives and work.

2017-01-12

UNDISCLOSED LOCATION IN BRITAIN — Russell Poole shows us eight delicate-looking cables inside a locked, fusebox-like contraption. "These are four pairs of fiber optic cables," the British engineer says.

This is part of the network of cables that lie along the bottom of the Atlantic Ocean, stretching from Britain to New Jersey, responsible for connecting the internet between continents.

There are about 350 cables that lie on the ocean floor of our planet. Without them, the internet would not function as a global network. Satellites, which transport the remainder of data, are the only alternative to these cables but they are costly and are less efficient. The box that Poole shows us, called the TGN Atlantic, is located in an inconspicuous gray industrial building in an equally inconspicuous industrial area near Britain's western coast. This building is a "landing station" that Poole runs. Due to security reasons, we are not allowed to reveal the exact location as it is a gateway to the internet network that serves Britain and Europe.

A sign outside the building says it's owned by Tata Communications, a subsidiary of the Indian conglomerate Tata, which owns a global network of fiber optic cables that TGN Atlantic is a substantial part of. Tata earns money by connecting the different locations of an international company, among other IT services. Having your own network of fiber optic cables is, of course, an advantage and telecommunication and internet companies pay to use the Tata network.

Apart from the cable leading to New Jersey, another cable connects the British landing station to Spain and Portugal and a further cable connects it to Africa via Portugal. Before data can be sent, it has to be processed and the cable's signals have to be enhanced. The TGN Atlantic boasts 149 signal enhancers that are located alongside the cable on the sea bed. These enhancers ensure that tiny blips of light within the fiber optic cables actually reach the other side of the Atlantic.

Shelves of batteries at a Tata building — Photo: Tata Communications

The technology that processes the data before it is sent is located inside a long row of cabinets that are kept cool by incessant air conditioning at the landing station. There is another room that contains nothing but large batteries located on two large shelves. "These generate energy for up to four hours in case of a power cut," says Poole. If that is not enough time to fix the problem, there are two more diesel generators in an adjacent room that have enough fuel to bridge a 16-day power outage.

But it's not blackouts that cause sleepless nights for Poole, but rather an unlikely peril lurking along the coastline. "Fishermen with trawling nets are the biggest danger to the cables," says Poole, who runs the landing station with the support of six employees. Although the cable locations are clearly marked on nautical charts, cables have been damaged in the past.

The actual cable itself is no thicker than a stick of glue. Within the reach of the coast, the cable is encased in steel tubing to protect it from anchors and trawling nets. If a cable has been damaged, special ships are sent out to sea to lift the cable from the seabed and repair the damage. This is a very expensive and elaborate task, just like the cable's initial installation.

It's still a lucrative business going by the rapidly increasing volume of data. More and more people go online to watch TV or chatting on video, while companies now can access software online rather than installing it on every PC within the office. Connected PCs, laptops and tablets are constantly sending data to one another.

Despite increased use, TGN Atlantic has not still reached full capacity because developments in transmission technology have led to companies being able to send more data than ever through cables that were installed in the "dotcom boom" of the 1990s. Tata Europe construction manager Sassoulas says that they are not planning on installing any more deep-sea cables in the near future as there is already "plenty of capacity."

Still, others are investing in new cables. Just this past summer a new cable was inaugurated between the U.S. and Japan, after an installation period of two years. Google was one of the companies that initiated the project, which cost about $300 million. In a joint venture, tech giants Facebook and Microsoft are installing a cable between Spain and the U.S. that would be ready for use in about a year's time.

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