In 1850, the world's first submarine cable was laid between North America and Europe. In 1866, the United Kingdom laid a submarine cable connecting the United Kingdom and the United States in the Atlantic.
Compared with terrestrial cable, submarine cable has many advantages: Firstly, there is no need to dig tunnels or support by brackets, so the investment is small and the construction speed is fast; secondly, except for the landing sites, most of the cables are in the seabed, due to the damage of the natural environment such as wind and waves and the interference of human production activities, the cable is safe and stable, with strong anti-interference ability and good confidentiality.
In 1876, after Bell invented the telephone, the submarine cable added new content, and the pace of large-scale laying of submarine cables in various countries accelerated. In 1902, the global submarine communication cable was built.
In 1960, the world's first laser came out, and people began to use the characteristics of laser energy transmission in the optical fiber to transmit information.
There are 32 countries and regions in the world that have established the most modern global communication network through submarine cable, which can carry out 300,000 telephone calls or data transmission at the same time.
Submarine cables have also developed rapidly in China. The Sino-Japanese submarine cable system built in 1993 that can open 7,560 telephone circuits. In 1997, FLAG was built in Nanhui, Shanghai, connecting 20 countries around the world and opening 120,000 telephone circuits. China began to build Sino-US and Asia-Europe two optical cables , and the total communication capacity will jump to 1.32 million.