The EllaLink submarine cable system is the only cable directly interconnecting Europe, Latin America and Africa in a single system: 5,900 km of subsea cable with four fibre pairs, designed from the outset for coherent optical transmission and data centre-to-data centre. The EllaLink submarine cable system is the only cable directly interconnecting Europe, Latin America and Africa in a single system: 5,900 km of subsea cable with four fibre pairs, designed from the outset for coherent optical transmission and data centre-to-data centre. The invention provides a method for converting an optical cable distance into a landmark position by using a distributed optical fiber sensing system, the distributed optical fiber sensing system for realizing the method and a computer readable storage medium. According to the technical scheme, the. Rather than loading many cables that are thousands of kilometers long on a ship to be laid out on the seafloor, it is overwhelmingly more efficient to install a single cable. NEC, as one of the top three enterprises in the submarine cable market, succeeded in prototyping the world's first four-core. ◆ By mounting and connecting 12-coupled-core multicore fibers with the same diameter as existing optical fibers suitable for mass production to commercial high-density multicore cables, and by developing large-scale MIMO signal processing technology, high-capacity long-distance transmission over. Fibre-optic Link Around the Globe (FLAG) is a 28,000-kilometre-long (17,398 mi; 15,119 nmi) fibre optic mostly- submarine communications cable that connects the United Kingdom, Japan, India, and many places in between. The ATX Long-Reach Digital Optical Transport solution.