Submarine optical cable systems carry more than 95% of international communication capacity and are the most important routing for trans-oceanic network transmission. Optical technology is the foundation for 5G and IOTs development demands, and the guarantee for communication security.

Based on the large-scale application of global digital technology, the internet flow has increased by 12 times compared with 2010, and along with the development of 5G, and other technologies, system capacity demand is increasing year by year. In the past 25 years, the capacity of single-core fiber has approached the Shannon-Hartley theory, and traditional communication can no longer meet the increasing demand for transmission capacity. SDM (Space Division Multiplex) technology has emerged, and submarine optic systems enter into the era of SDM1.0 .

This report mainly introduces the history and development trend of submarine optical cable system, and according to the surge of capacity and new transmission requirements, a new generation based on SDM of repeatered trans-oceanic submarine cables is proposed and designed.