SUBMARINE CABLE

A submarine communications cable is laid beneath the sea to carry telecommunication between countries. The submarine cables were used initially for telegraphic transmission. It was later used for telephone communication however now it is used to transfer data. Modern submarine optical fiber cable is today the backbone of all internets. The following table shows the details of International communication traffic carried by satellite and submarine cables:

Year	Satellites	Submarine Cables
1990	80%	20%
1995	44%	56%
2006	5%	95%
2010	1-2%	98-99%

In the very initial stages, Coaxial cable was used in the core of submarine cables. The first optical fiber cable was TAT-8 which went into operation in 1988; it comprised of two operational pairs and one back up pair. Earlier optic fiber cables had a single point to point connection. With the growth in submarine branching units, a single cable was able to serve more than one destination system. However modern cable systems comprise of self healing ring which helps it to improve its superfluous criterion. The more recent development in the self healing ring was the introduction of mesh networks. In this type of network fast switching devices are used which makes it possible to transfer services apathetic to the higher level protocols. The total carrying capacity of sub marine cables is terabits per second.

A cable landing point is the location where a submarine or other underwater cable makes landfall. These points are usually carefully chosen to be in areas that have little marine traffic, without strong currents, so that the chances of cable being damaged can be reduced.

Dense Wave Division Multiplexing (DWDM) ,which enhances the capacity without adding fibers, is used in submarine cables. At the other end, DWDM demultiplexers capable of distinguishing each wavelength without crosstalk. For maintaining the level of the communication signals EDFA are used. Submarine cables can be broken by fishing trawlers, anchors, earthquakes, undersea avalanches, and even shark bites. The average incidence of cable faults was 3.7 per 1,000 km per year from 1959 to 1979. That rate was reduced to 0.44 faults per 1,000 km per year after 1985, due to widespread burial of cable starting in 1980. Based on surveying breaks the repair ships with several types of grapple is used.

The submarine cable is having all the advantages of optical fibre. Moreover, it has following benefits over satellite communication:

• Cost effective in long term
• Fulfills increased demand of bandwidth
• Better security
• More dependable installation
• Better repair practices

BUSINESS ASPECT

Sub marine cable business is a booming industry with submarine cable business fast approaching revenue peaks that happened during the Internet boom in early 2000, according to Alcatel Lucent a market leader in sub marine cable suppliers. The rapid growth which is currently being witnessed is mainly driven by investments in up-and-coming markets and high demands for services including mobile broadband, movement towards bigger IP based domains, SAT, teleports and long distance calls. There is a competition amongst the telecom operators and suppliers around the globe to install new submarine cable capacity to enhance data links to regions like sub-Saharan Africa and Asia, that includes south and east Asia. Thus there is a clear shift in focus from Europe to Asia and Africa as far as submarine cable business is concerned.

In Asian region, specifically India, leading Telco Bharti Airtel is expanding its submarine cable offerings globally to target business opportunities in over 100 countries by 2013, Reliance FLAG is working on NGN System – 2 connecting India and Kenya with potential extension to South Africa.

Submarine cable projects in African and sub-Saharan region including East African Submarine cable(EASSy) ,East African Marine System(TEAMS) and  the new undersea cables surrounding Africa will boost the broadband penetration rate from 3.2 percent in 2010 to 6.8 percent in 2015. New undersea cables will drive the growth of total broadband users in Africa from 40 million in 2010 to 92 million in 2015 at a CAGR of 18 percent, while revenue will increase at a CAGR of 16 percent in the same period to US$20 billion.

All these projects in Asia and Africa are expected to have a positive impact on all sectors - from education, to health, to entertainment, helping drive economic growth and creating job opportunities. An expanding network and falling prices are expected to fuel explosive growth in mobile broadband in Africa over the next few years, particularly Nigeria, which has overtaken South Africa to become the continent's largest mobile telecoms market.Enhanced capacity offered by these submarine cable systems will bring more competition among big operators such as South Africa's MTN and India's Bharti, which completed a $9 billion acquisition of the African operations of Kuwait's Zain.

Various cable systems have been formed all over the world over a period of time, considering the importance of submarine cables.The transatlantic cable systems(TAT series cables),South East Asia – Middle East – Western Europe cable systems(SEA –ME – WE1,2,3,4) and South Africa’s submarine cable network(SAT 1,2,3) are some of the submarine systems spread across the globe.

Submarine cable design & operations are constantly evolving. Future systems are expected to have even greater capacity and reliability. Cables, with sensors to detect chemical & physical changes, are planned for maritime & coastal defenses.