Wednesday, March 28, 2012
Looping fibre optics from Japan under the Arctic ice will improve internet performance – but is easier said than done
THE retreat of sea ice is bringing 21st-century communications to the Arctic.
In mid-August, construction should start on the first submarine fibre-optic cables to cross the Arctic Ocean, providing digital shortcuts between London and Tokyo, Japan.
Two cables are planned through the fabled North-West Passage above North America, while a third is planned along the Russian coast.
The longest of these links will become the world's longest single stretch of optical fibre.
Sea ice and icebergs pose unique challenges. Ships rated to work in ice-ridden waters are needed to lay the cable, and operations are possible for only a few months of the year.
Yet there are advantages to laying cables in the Arctic, says Denis Tsesarenko, a director of the Polarnet Project, which is building the Russian Optical Trans-Arctic Submarine Cable System (ROTACS).
Once laid, the cable should be largely safe from the biggest threats to cables in warmer waters: fishing trawlers and ships' anchors are extremely rare in the Arctic.
Meanwhile, a 15,600-kilometre link via the Canadian Arctic, to be built by Arctic Fibre of Toronto, Canada, will cut the present round-trip time, or "latency", between London and Tokyo from 230 milliseconds to 168 milliseconds, claims company president Doug Cunningham
Reduced transmission time will be a boon for high-frequency traders who will gain crucial milliseconds on each automated trade.
Optical amplifiers will boost signal strength every 50 to 100 kilometres.
The firm also plans to drill a tunnel 40 metres deep to take a shortcut through the Boothia isthmus in the Canadian Arctic - a thin strip of land that connects the Boothia peninsula to the mainland.
Isolated Arctic communities will also be connected by extra sections of cable that branch off from the main one.
A third project, by Arctic Link, a firm based in Anchorage, Alaska, is planned to begin in 2014.
A big plus for the Arctic cables is that they avoid failure-prone "choke points" such as the Luzon strait near Taiwan, the strait of Malacca between Indonesia and Malaysia, and the crowded and politically unsettled Middle East.
A single landslide or a ship dragging its anchor in these areas can break several cables, disrupting internet traffic.
Crucial parts of the North-West Passage are nominally ice-free from 20 August to 5 October, but you cannot rely on the fact that the ice will be open, says Chris Carobene, managing director for marine construction at TE SubCom, based in Morristown, New Jersey, which is not currently involved in these projects.
Ships must be built to withstand the pounding of ice as well as waves.
"Your cable ship needs a polar-ice rating even when you are working with an ice breaker," he says.
Standard cable ships are not built to withstand ice, so ice-rated ships built for other purposes will be converted to lay the cables.
Icebergs can plough more than a metre into the ocean floor, endangering cables.
Greenland's icebergs extend to depths as great as 170 metres below the sea surface, so Arctic Fibre will lay cable at least 600 metres deep in the Davis strait, where icebergs are most likely. The underside of sea ice also has ridges, or "bummocks", that reach depths of 18 metres, so Arctic Fibre aims to stay at least 50 metres down.
As Carobene says: "Ice is just another risk our industry has to manage."