ROVworld Subsea Information

Nexans installs a fibre-optic cable and provides rapid data transmission across
Date: Monday, December 17, 2007 @ 09:00:00 EST

Nexans installs a fibre-optic cable and provides rapid data transmission across Lake ConstanceNexans, the worldwide leader in the cable industry, has just completed a contract for Stadtwerke Konstanz Gmbh to lay a submarine fibre-optic cable across Lake Constance, providing a new ultra-fast data communication link between the German towns of Konstanz and Friedrichshafen.

Konstanz and Friedrichshafen are on opposite shores of Lake Constance, the large freshwater lake on the Rhine between Germany, Switzerland and Austria. Stadwerke Konstanz, the local utility, wanted to upgrade the data communications link between the two towns, however laying the cable on land would have involved taking a long route around the lake with expensive excavation work. The direct route, with the cable laid on the lake bed, has proved more cost-effective.

The fibre-optic cable, weighing over 30 tonnes and 26 kilometres long, was manufactured and delivered by Nexans in one single continuous piece thus eliminating jointing operations. Beneath a robust outer sheath, it comprises four stainless steel sheathed bunched conductors, each consisting of 48 monomode fibre- optic cables. Each individual fibre is capable of ultra-quick transmission of large amounts of data, digital television signals and an almost unlimited number of telephone conversations.

Environmental protection

Lake Constance fiber opticA condition for Nexans receiving the order was that the materials used in the construction of the cable must not harm the drinking water reservoir, as many towns and communities, right up to the northern border of Baden-Württemberg, procure their water from Lake Constance. Care also had to be taken to ensure that laying the cable would not harm any migratory or breeding birds, fish spawning grounds or plant growth near the river bank.

Cable installation

The laying of the fibre-optic cable, which was manufactured in the Nexans factory at Rognan, Norway, proceeded without a hitch thanks to the in-depth planning and preparatory work. It was carried out by a converted passenger ferry that took just 13 hours to cover the route from Friedrichshafen to Konstanz. A GPS location system ensured that it remained in the correct location, while reference points on land were also used to monitor its precise position.
The laying process was managed by experts from Nexans in Norway who have extensive experience in working on the open sea, as large inland waters also present their own challenges. Lake Constance is up to 250 metres deep. This meant that the cable had to be lowered at a perfectly controlled speed to ensure a smooth landing on the lake bed. It required a special regulating device mounted on the ferry.

For this project, an international Nexans team was created with experts coming from Germany (Mönchengladbach), Norway and Switzerland to ensure the manufacturing, installation and connection of this fibre-optic cable.

Data transmission capacity for hire

Stadtwerke Konstanz GmbH is now hiring out the data transmission capacity of the new fibre optic cable to customers such as internet carriers which offer high-speed internet access or companies which require a dedicated line. Initially, 144 of the 192 fibre optic cables will be put into service; the remaining cables will form the back up for future developments.

This article comes from ROVworld Subsea Information

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