Submarine Optical Communications System Providing Global Communications Network

The capacity of the global communications network is being progressively increased to handle the rapid growth in telecommunication traffic generated by the Internet. Fujitsu supplies submarine optical cable systems that can provide the huge capacity and short transmission delay required by carriers. There are two ways to increase capacity: construct a new submarine cable system or upgrade the existing one. For the latter, in particular, coupler insertion technology has been established. This allows the existing submarine line terminal equipment (SLTE) and new SLTE to co-exist in one system. As the existing submarine portion will continue to be used unchanged, this technology can reduce the amount of work done at sea and contribute to cost and lead-time reductions. Fujitsu has chosen to use return-to-zero differential phase shift keying (RZ-DPSK) technology to improve the upgradeable capacity and has applied it to several transpacific projects.