Submarine communications cables

Introduction to submarine communications cables

In the last 25 years, submarine cables have become a dominant element in the world's economy. It is not too much to say that, without them, it is hard to see how the present world economy could function. The Internet is essential to nearly all forms of international trade: 95 per cent of intercontinental, and a large proportion of other international, internet traffic travels by means of submarine cables. This is particularly significant in the financial sphere: for example, the SWIFT (Society for Worldwide Interbank Financial Telecommunication) system was transmitting financial data between 208 countries via submarine cables in 2010. As long ago as 2004, up to 7.4 trillion United States dollars were transferred or traded on a daily basis by cables (Rauscher, 2010). The last segment of international internet traffic that depended mainly on satellite communications was along the East coast of Africa: that was transferred to submarine cable with the opening of three submarine cables along the East coast of Africa in 2009-2012 (Terabit, 2014). Submarine cables have advantages over satellite links in reliability, signal speed, capacity and cost: the average unit cost per Mb/s capacity based on 2008 prices was 740,000 dollars for satellite transmission, but only 14,500 dollars for submarine cable transmission (Detecon, 2013).

Submarine telegraph traffic by cable began between England and France in 1850-1851. The first long-term successful transatlantic cable was laid between Newfoundland, Canada, and Ireland in 1866. The early cables consisted of copper wire insulated by gutta percha, and protected by an armoured outer casing. The crucial development that enabled the modern systems was the development of fibre-optic cables: glass fibres conveying signals by light rather than electric current. The first submarine fibre-optic cable was laid in 1986 between England and Belgium; the first transatlantic fibre-optic cable was laid in 1988 between France, the United Kingdom and the United States. It was just at that time that the Internet was beginning to take shape, and the development of the global fibre-optic network and the Internet proceeded hand in hand. The modern Internet would not have been possible without the vastly greater communications possibilities offered by fibre-optic cables (Carter et al., 2009).