Japan's NEC and NTT have announced the successful completion of a transoceanic-class 7,280 km transmission experiment utilising a coupled 12-core multicore fiber, comprised of 12 optical signal transmission paths within a standard outer diameter optical fiber (0.125 mm). A coupled multicore fiber is an optical fiber where signals transmitted in each core are separated and demodulated through post-processing, based on the assumption that optical signals leaking from multiple optical transmission paths (cores) in the fiber interfere with and influence each other.
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Transoceanic-Class Transmission Experiment
This transmission infrastructure technology is poised to contribute significantly to the realisation of large-capacity optical networks, including future optical submarine cables, the technology partners announced in a joint statement on Thursday.
NEC highlighted the pressing need to increase transmission capacity per optical submarine cable system, alongside the growing global adoption of 5G and the escalating demand for communication needs. In response, NEC is currently engaged in a project aimed at deploying a long-haul optical submarine cable system using two-core multicore fiber with two optical transmission paths.
Multicore Fiber Technology
In their efforts to develop transmission technologies and address issues related to Crosstalk in Multicore Fiber and Non-uniform Delay and Loss, NEC and NTT have developed various technologies, including an algorithm by NEC for demodulating received signals using Multiple Input Multiple Output (MIMO) technology, while NTT has developed a coupled 12-core multicore fiber optical transmission line.
By combining these technologies, NEC and NTT conducted long-distance transmission experiments over 7,280 km, simulating a transoceanic-class optical submarine cable. The companies claimed that they achieved a world-first in accurately demodulating 12-spatially multiplexed optical signals offline, according to the official release.
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Future Implications and Commercialisation
The two companies will further advance the research and development of these technologies to commercialise them as a long-haul, high-capacity optical submarine cable system and terrestrial core network system. Reportedly, this initiative is expected to contribute to the realisation of a high-capacity optical transmission infrastructure in the IOWN (Innovative Optical and Wireless Network) concept and beyond 5G/6G era in the 2030s.
