Hello,
Today, I will introduce you the Knowledge of submarine cables.
In recent years, global Internet transportation methods have generally replaced satellites with transoceanic submarine cables to ensure transmission rates and save operating costs. So how is the submarine cable made? How about the laying process? How fast is the transfer rate? How popular is it now? Here are some basics about submarine cables.
Materials:
The core of the submarine cable is made of high-purity optical fibers as thin as hair, and the internal reflection is used to guide the light along the path of the optical fiber. The submarine cable must be able to withstand the huge pressure of 8 kilometers underwater, which is equivalent to putting an elephant on the weight of the recognized thumb. The deep-sea cable manufactured by NEC is made of lightweight polyethylene, and the entire cable is only 17 mm thick.
Production process:
In the manufacture of submarine optical cables, the optical fiber is first embedded in a jelly-like compound to protect the cable from damage even in contact with seawater. The fiber optic cable is then inserted into the steel pipe to prevent it from being damaged by the pressure of the water. Next, it is wrapped in a steel wire with a very high overall strength, and it is sheathed in a copper pipe, and finally a protective layer of polyethylene material is sheathed. Close to the coast of the continental shelf, submarine cables are usually laid using lightweight cables with stronger wires and covered with an asphalt coating to prevent seawater corrosion.
Submarine cable laying:
The submarine cable laying mainly includes three stages: cable routing survey and cleaning, submarine cable laying and burial protection. When laying the cable, control the sailing speed of the laying boat and the cable release speed to control the water entering angle and the laying tension of the cable to avoid damage to the cable due to too small bending radius or excessive tension. Among them, when laying in the shallow section, the cable laying boat stopped at a distance of 4.5 kilometers from the coast, and was towed by the tractor on the shore to pull the cable placed on the floating bag ashore. After the cable landed, the floating bag was removed to sink the cable to the bottom of the sea. When laying in the deep sea, the cable laying ship releases the cable, and the underwater monitor and underwater remote control vehicle are used for continuous monitoring and adjustment to control the forward speed and direction of the laying ship and the speed of laying the cable so as to avoid uneven areas. And rocks to avoid damaging the cable.
Capacity:
The submarine cable can carry up to 80Tbps of data, which is equivalent to transmitting 4.7GB of capacity in one second.
History of development:
The first submarine cable in the world was the cable that passed through English in 1851, more than ten years before Bell invented the telephone. As early as 1995, half of communication transmission was transmitted through satellites. Compared with previous transmission methods, the development of submarine cables has grown tremendously. Hundreds of submarine cables connect all parts of the world, while satellites are relegated to the second line, only used to connect remote areas and some small islands.
Popularity:
99% of transoceanic Internet data transmission is now transmitted through submarine cables. At present, the submarine cable is 39,000 kilometers long and connects 33 countries and four continents.
Fault history:
Although the shark was recorded by the camera to damage the submarine cable once, the submarine cable failure caused by sharks and other fish after 2006 was less than 1%.
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