The focus of this article is submarine cables. They were used for the first time in international telegraphy in 1850s. As for the first transatlantic telephone submarine cable, it had operated only 90 years after its set-up. Regarding the first transatlantic telegraphic submarine cable based on optical fiber, it operated for the first time in 1988 between the United States and Europe.
1-Telegraphic submarine cables
The first tests of transatlantic telegraph cables took place for the first time in 1850s. They faced major technical problems, particularly due to their weights. Cable’s weight could reach at that time almost 15 tons per km, while current cables that are based on optical fiber barely weigh between 200 and 250 kg per km, depending on their capacities. Moreover, the first submarine cable installed in 1857 broke at sea at a depth of 3700 meters because of its weight. The second attempt however was successful and was released on July 29, 1858. But this second cable only worked for three months. It was not until 1866 that the world could witness the laying of the first transatlantic telegraphic submarine cable which lasted longer. This first successful underwater telegraphic link operated between Ireland and Canada (Newfoundland). Regarding the first French transatlantic cable, it was laid in 1869. By the way, it should be noted that submarine cables, actually worked on small distances, well before. Among these first submarine cables made, we could cite the one that was set up in 1851 between Dover in England and Cap Griz-Nez in France, for the objective to support financial transactions between the stock exchanges of London and the one of Paris at the time. In fact, it took 60 years to see the layout of the global network of telegraphic submarine cables, which was completed around 1926 with about 200,000 km of cables. On the Moroccan side, it was in 1880 that the British telegraph company founded in 1872, the Eastern Telegraph Company, and installed a telegraph cable to connect Tangier to Gibraltar, which was the first installation of the submarine cable connecting the Africa to Europe. In Morocco, until 1908, Tangier was the only city to be wired by telegraphy communications. Three submarine cables, an English one, a Spanish one and a French one made it possible to carry out these communications with the whole world. In 1913, the Moroccan telegraph network was well installed in its turn! All seaports of Morocco were connected. The telegraph office of Casablanca was connected by a submarine cable with France, via Brest, and with Dakar through the submarine cable Casablanca-Dakar. The city of Oujda controlled the telegraphic traffic with Algeria and Tunisia. Casablanca was also connected to France via the Oran-Marseille cable. For example, in 1930 the Casablanca-Brest submarine cable set up in August 1914 allowed a large part of telegraphic traffic to flow to France. When this cable was occasionally damaged, the Casa-Médiouna TSF radio station took over.
2-The submarine telephone cables
Despite the commercial exploitation of the fixed phone in the United States, as early as 1877, and in France as early as 1879, it was not until 1956 that the first transatlantic submarine cable appeared.
While telegraphic walrus pulses were easier to transmit over long distances, the transmission of intelligible telephone signals proved very difficult from the beginning. For this reason, the first submarine cable was only inaugurated in 1956; which means 90 years after the installation of the first telegraph submarine cable. The telegraphic communication is relatively easy because it is established as soon as the electrical pulses are detected at the other end and whatever the distortion of these pulses and the variations of their amplitude with time. On the other hand, speech intelligibility requires careful signal processing and depends on the accuracy with which variations in the amplitude and frequency of sounds are reproduced.
Even though, the plans of realization of this connection were defined as early as 1953, the first transatlantic submarine telephone cable, the TAT 1 (Transatlantic 1), was launched until September 25, 1956. This cable which had a capacity of 48 channels has designed to connect the United States and Canada to the United Kingdom, with possibilities to serve other Western European countries. The achievement of the longest and most spectacular submarine cable at the time was the one connecting South Africa to Portugal in 1960. SEA-ME-WE cables (South East Asia – Middle East – Western Europe) are submarine cables between Europe and Asia. In 1986, SEA-ME-WE 1 was installed as a copper coaxial cable for the transmission of analogue telephone signals between Europe, the Middle East and South-East Asia. It was, at the time, the longest telephone cable in the world with 13,585 km, and the first cable of this type to be installed in the Indian Ocean.
It should be noted that international telephone calls were already possible by radio across the Atlantic since 1927 thanks to the connection between Rugy (England) and Rocky Point (United States). Morocco was connected to France by a first analog submarine telephone cable in 1966. This submarine cable connected Tetouan to Canet in France with a capacity of 96 circuits.
The first Transatlantic Telecoms Fiber Optic System TAT 8 was commissioned in 1988 between the United States, France and Great Britain. It offered a capacity of 7860 circuits, superior to that of its predecessors analog cables the TAT 6 and TAT 7 together (6,000 circuits). With the arrival of optical fiber in submarine cables, improvement in transmission capacity has been tremendous and these fibers have helped to greatly mitigate the « very long distance » effect, and hence this resulted in a worldwide fall in telecommunications prices, both on data and voice services. According to World Bank expert Mohsen Khalil, the unit cost of a fiber optic circuit has decreased by 70% between 1980 and 1990. And according to OFS, a fiber leader in the US, the cost of raw fiber has decreased about 95% since the 1980s to present days and its installation techniques have greatly advanced.
After the TAT 8, which allowed 40,000 simultaneous telephone calls, TAT 12 and TAT 13 were available in the 1990s to allow new Internet connections. And during the 2000s TAT 14 was set up, which was 64 times more efficient than the previous ones, and allowed 8 million simultaneous communications of multimedia type. The SEA-ME-WE 2, the world’s longest optical fiber cable at 18,337 kilometers, was commissioned in 1994, connected 14 countries and three continents. Its installation began in 1988. The SEA-ME-WE 5 is designed with very high speed (100 Gb/s) technology combined with wavelength division multiplexing (WDM). The SEA-ME-WE 5 offers a transmission capacity of 24 Tbps on 3 pairs of fibers. It complements the already existing submarine cable SEA-ME-WE4. The completion of SEA-ME-WE 5 was achieved in 2016. The Orange France group is involved in all these and other projects, including the installation of the ACE cable (Africa Coast to Europe), which starts from France and along the entire west coast of Africa to eventually reach South Africa.
The first fiber-optic cable called « Eurafrica », using the so-called Plesio chronous Digital Hierarchy (PDH) technology linking Morocco to Portugal and France, was inaugurated in 1992. And in 1994, the submarine fiber optic cable using the technique (Synchronous Digital Hierarchy or SDH) between Morocco (Tetouan) and Spain (Estepona) was put into operation. In 1999, Morocco interconnected Tetouan via a submarine station to 33 other countries using the digital fiber optic cable SEA.ME.WE3., which is an international cable with a total length of 39,000 kilometers and a capacity of 20 Gb / s or 30,240 circuits.
3-The vital submarine cables for our exchanges on the Internet
It seems incredible although it reflects the reality; the 430 submarine fiber optic cables, installed deep in various seas, carry 99% of the international traffic while the majority of users think that this traffic goes through satellites! The strategic importance of these submarine cables pushes some internet giants to be interested in too. For example, Google has invested in ‘Faster’, a 12,000-kilometer cable that connects the US West Coast to Japan, which was commissioned in 2016. In September 2017, the fiber submarine cable of 6,400 km called « Marea » was initially implemented from Microsoft and Facebook linking the Datacenter of Virginia Beach in the United States to those of Bilbao in Spain with a power of 160 terabits (10 to the power of 12 bits per second).
Currently, more than 430 optical fiber submarine cables are in use around the world for a total of about 1.3 million km, which represents more than 32 times a tour around our planet earth! Their capacity in bits speed is several tens of Terabits / s! In 1992 the submarine cables transported 100 GB per day; in 2002, 100 GB per second and in 2016 more than 26,600 GB per second. From 2016 until 2018, this internet traffic has grown by 35% annually! The latest generations of optical fiber cables allow, inter alia, an improvement of latencies. According to Mr. Abdelouahid Aissa, a telecom engineer and expert in the field, a communication from the United States to China could be currently set in only 120 milliseconds. Indeed, reducing the nanosecond delay in communications between global stock exchanges can result in millions of dollars in gains for stock market players! For illustration purposes, the creation of the submarine cable by Hibernia Network in September 2015, linking Canada, Ireland and Great Britain saved five milliseconds of speed in High Frequency Trading (THF) between London and New York stock exchange. This fiber optic cable is considered the most efficient in terms of latency. Improving latency and reducing information exchange time constitute another target set for submarine cables as well as to other networks such as 4G (LTE) and 5G!
When analyzing the evolution of submarine cables and the various related risks from 1850 to the present days, we can only pay a warm tribute to scientists, engineers, technicians, managers, lawyers, financiers and businessmen, for the commendable efforts they have made, especially during the periods of uncertainty and conflict over the construction of these submarine cable networks. We will continue in fact to deploy these ongoing efforts in order to ensure universal and global connectivity, despite the various risks. Risks which, according to Mr David Rogerson, an expert from the ITU, push telecom operators and stakeholders to fix a WACC (Weighted Average Cost of Capital) more than twice the one applied to terrestrial cables, for instance.
As research and innovation have no limits, telecommunications will certainly open up in the future to unexpected new horizons, because as René Guenon, the French philosopher at the beginning of the 20th century, said: « No one can stop progress! « .
Ahmed Khaouja, Telecom Engineer. Former official of the Ministry of PTT Morocco. Ex Employee of ONPT Morocco. Ex Employee of ANRT Morocco. Currently Director of PTT Morocco and ITU Expert.
Translated by Ali Benseddik, French-English translator .Telecom economist.