Submarine cable
2. Polyethylene terefthalate tape.
3. Braided steel wires.
4. Waterproof aluminum barrier.
5. Polycarbonate.
6. Copper or aluminum tube.
7. Vaseline.
8. Optical fibers.
A submarine cable or interoceanic cable is a copper or fiber optic cable installed on the seabed and intended primarily for telecommunication services.
However, there are also submarine cables for the transport of electrical energy, although in this case the distances covered are usually relatively small and they are also inserted into a special pipe to avoid risks of contact with water since it handles high powers.
Currently, submarine fiber optic cables are the basis of the global telecommunications network connecting the continents. The submarine cable is shown to be a robust and efficient solution, due to its resistance to inclement weather, lower latency, and greater width bandwidth than satellite communication, all of which positions it as a more reliable infrastructure with greater capacity, once installed and tested.
Communication via satellite has been relegated since the 1990s to the transmission of specific sports and/or cultural events, the communication of extremely remote sites, and maritime / aeronautical navigation. It takes advantage of the flexibility of being able to "go up to the satellite" instantly wherever the "footprint" satellite allows, and even move without losing connectivity, something that cable cannot provide.
History
Regarding the telecommunication service, the first cables, intended for the telegraph service, were made up of copper wires covered with an insulating material. As early as 1845, submarine cable tests were being carried out in Portsmouth, although sufficient reliability had not yet been achieved. The invention of a waterproof insulation called gutta-percha, developed in 1847 by the German Werner von Siemens. allowed the Submarine Telegraph Co. laying, in 1852, the first submarine cable linking the United Kingdom and France through the English Channel. Although it was cut by some fishermen shortly after it was installed, this milestone proved that the submarine cable worked and unleashed an unbridled race for its development in the world.
Between 1852 and 1854 different lines were built between Ireland and Scotland, between Wales and Ireland, between Corsica and Sardinia, between Sweden and Denmark and various other small lines (usually less than 25 nautical miles). Some worked well and others not so well, but all these works allowed to gain experience on the laying and the durability of the materials.
In 1855, the project to lay the first transatlantic cable was approved, which was put out of service in a short time. In 1865 the second project was launched. The largest existing ship at the time, the Great Eastern, was used for this purpose. This cable did not come into operation until 1866 and linked Ireland and Newfoundland. In 1868 a cable was finally laid across the Atlantic Ocean connecting Ireland with Canada. This cable greatly optimized the communication between the United States and Great Britain and drastically reduced the time in which messages could reach their destination: from days (the time it took ships to deliver the message on the other coast) to just hours. It was the American telegraph specialist Cyrus West Field and the Irish physicist and mathematician William Thomson, later known as Lord Kelvin, who ventured to install this cable in a context where the idea of being able to communicate over long distances in a short time was even more important than electric light.
The procedure consisted of meeting two ships halfway and then transporting each end of the cable to each of the coasts, 3,000 kilometers apart. Until then, the idea of a submarine cable was not possible because a sufficiently resistant material was not available. With the implementation of gutta-percha, a material obtained from the sap of some trees, the cable could be covered enough to allow underwater connections. Although the first attempt was a failure, after the successful installation in the English Channel it soon became famous in Europe and was installed in different nations. Important connections were made in the Mediterranean Sea and in the Black Sea. It is estimated that in 1855 at least twenty-five submarine cables had already been installed. This was what allowed Field and Thomson to try to connect their two nations, which at the time their political context demanded a better way to stay connected.
The laying difficulties were considerable. Also those of exploitation, due to the high attenuations suffered by the signals as a consequence of the capacitance between the active conductor and the ground connection and due to the insulation problems. Many of these problems were due to sabotage by the shareholders of the shipping companies, who drove nails and thus pierced the insulating layer of the cable. Many men and painstaking and conscientious work had to be employed to repair them. The progress of this was economically detrimental to shipping companies.
After this connection failed, several investors withdrew from the project. Six years later, an attempt was made again to connect both nations.
Ideologically, it could be said that the cable served to consolidate the synchronization of the Western world between two major powers. It also served to establish the first great notion of a fully connected world. It even opened the door for further steps to be taken in relation to the development of communication connections, first for telegraphy and then for telephony, equipped with submerged amplifier repeaters, with power supply through the same conductors used to transmit the conversation..
In the 1960s, submarine cables made up of coaxial pairs were installed which, using frequency division multiplexing, allowed a high number of analog telephone channels, on the order of 120 to 1800, which was a lot for the time.
In the 1980s, submarine fiber optic cables began to become popular, using wavelength division multiplexing, the same philosophy but this time using different wavelengths from laser emitters. Thus, they opened the way for the simultaneous transmission of a large number of digital signals carrying voice, data, television, Internet, etc. with transmission speeds of up to 1000 Tbit/s.[citation required]
Although the cable was part of a communication development, you can also think about all that it meant. In a world where the notion of “connectivity” was just beginning to be clarified and where the idea of understanding society through a network metaphor was practically non-existent, there were those who ventured to attempt this great feat..
Installation
With an element similar to a hoe but large, handled by underwater robots, a groove is created where the cable will rest, a groove that will later be covered with sand deposited by the ocean current. This is done in areas where the depth is shallow or other risks could appear, since when the depth is significant, the cable simply rests on the seabed. The most difficult thing is to determine the depth of the ocean. The seabed consists of unevenness, which means that there are conflicting areas in very different conditions to locate the cables. To do this, the most suitable areas to place them are studied in depth.
In the Japan Trench, at a depth of 8000 meters, there is an underwater cable. The cable must be considerably longer than the depth at the time of its installation: the ship is in motion while it lays the cable and the angle it forms from the deepest area means that 16 kilometers of cable are needed for the 8000 meters deep.
Features
Cables these days are not very thick, they can reach the size of a human arm. Paradoxically, the greater the depth, the less mechanical protection needed, as there is less chance of damage to the cable by anchors, trawls, or others. They usually have the optical fibers in the center, plastic coatings, steel cables for mechanical resistance, copper conductors for powering the repeaters, and an outer sheath of polyethylene terephthalate to completely insulate it.
Data transmission capacity
3,840 giga-bits per second, that is, 102 DVD discs in those seconds, this is possible through fiber optics. A cable consists of 16 fiber strands, therefore 1700 DVD discs are filled per second, over 60 terabits per second.[citation needed]
Complications
Repairing a cable that deep is impossible, so they are fixed on the surface. Damaged ends are salvaged with an underwater robot, and the damage is repaired, bonded or fixed aboard special ships. There are not many ships that are dedicated to this work.
There are several reasons why cables get damaged, but basically it's from ship anchors, fishing nets, or fish. The marine fauna can eat the coating of the cables (sharks), attracted by the magnetic fields. Fortunately, new cable designs address this problem and reduce the possibility of cuts or complications from these causes.
Other cases that are contemplated are earthquakes. In 2006 one with magnitude 7.0 broke eight cables in the Taiwan area, seriously affecting communications in China. A total of eleven ships spent 49 days working on the repair.
Currently, movement recognition systems are being incorporated on the ocean floor for possible earthquakes, which could lead to something more complicated. It is known that they originate there, so we can count on the speed with which the cable can warn of what is happening, this gives us a great margin of maneuver to prevent situations in cities.
Cables are currently not protected by countries.
"There are between 100 and 150 undersea cable cuts every year".[citation needed]