Do you know the way in which major undersea cables laid in the ocean?
The undersea cable connection haven’t surfaced overnight. It started back in 1854, installation began on the first transatlantic telegraph cable, which connected Newfoundland and Ireland. Now, the technology turned more captivating. Laying the undersea cables is surely the laborious though enthralling task.
Modified and exceptionally designed ships are employed for laying the underwater cables that carries the submarine cables on board and then slowly lay them on the seabed as instructed by the cable operator. These ships are capable of carrying 2,000 km long cables.
Structure of Underwater Optical Fiber Cables:
Underwater cables are optical fiber cables specifically designed for the submarine operations such that they shouldn’t be prone to easy abrasion and wear & tear. They are constructed to resist severe conditions as well as of extreme pressure due to the heavy flow of water. They consists of 8 layers which are given as:
- 1. Polyethylene
- 2. “Mylar” tape
- 3. Stranded metal (steel) wires
- 4. Aluminum water barrier
- 5. Polycarbonate
- 6. Copper or aluminum tube
- 7. Petroleum jelly
- 8. Optical fibers
The capacity of laying cables per day not only depends upon the capacity of the ships employed but also depends upon several other factors like the sea conditions, the type of plough used, and the ocean-bed on which the cable is to being lead down. Usually, the cable ships can laid down the cables between 100-150 km of cable per day, but the newer ships and the ploughs can make it up to 200km of cable laying in a day.
These cables carry Dense Wavelength Division Multiplexing (DWDM) laser signals. They carry the signals at the rate of terabytes per second. They often employ the optical repeaters to amplify the signals timely, as they attenuate over prolonged distances. Their lifespan is of 10 years and the cost entirely depends upon the length of the cable.
Why don’t we prefer satellite communication over the undersea cables?
Even when the large communication satellites are capable of covering the wide geographical areas, they do spend a billion dollars per communication line. On contrary, the cost for typical undersea communication is somewhere between $100m-$500m. Also, optical fibres offer the point to point communication, which absolutely ensures the delivery of the information.
Process of Laying Underground Cables
The process the laying the cable starts from the landing station. Landing station is the place where a long cable section is linked to the landing point & from there it is extended to a few miles inside the sea. Another end of the cable is connected to the ship and there ship initiates the laying process. However, the coiling of cable which is hundreds or even thousands of miles long is placed in cargo of the ship. This process of coiling takes three to four weeks to complete. These cables are laid down with the help of plough.
The cables may or may not be detectable over the surface area. However, to treat the damaged cables submersibles, divers or the robotic arms with lights & cameras are used to look after the cuts in the seabed, which are later joined by splicing.