Nokia and Facebook break subsea cable performance records

Created April 3, 2017
Applications and Research

Nokia and Facebook have set new spectral efficiency and capacity records in multiple submarine field trials over a 5,500 km submarine cable between New York and Ireland. The submarine field trial of Nokia Bell Labs’ new Probabilistic Constellation Shaping (PCS) technology used shaped 64-QAM, which achieved a record spectral efficiency of 7.46 bits/s/Hz and increased the stated capacity of the system by almost 2.5 times.

The test also included a successful 11,000 km round trip submarine transmission using shaped 64-QAM, achieving a record spectral efficiency of 5.68 bits/s/Hz, and a first demonstration of 200 Gbits/s and 250 Gbits/s wavelengths and 16-QAM modulation over a transatlantic submarine route using a real-time coherent DSP.
Dr. Stephen Grubb, Global Optical Network Architect at Facebook, commented: “Facebook wants to increase the pace of innovation and adoption of next-generation optical technologies. This field trial with Nokia demonstrates that the scalable optical technology of PCS together with narrow linewidth laser sources can achieve capacities extremely close to the Shannon limit.”

“By demonstrating promising areas of Nokia Bell Labs research such as PCS, as well as coherent technologies available today, we hope to chart a path forward for the industry towards higher capacities, greater reach, and more network flexibility,” added Nokia Head of Optical Networking, Sam Bucci.

John Williamson




This article was written
by John Williamson

John Williamson is a freelance telecommunications, IT and military communications journalist. He has also written for national and international media, and been a telecoms advisor to the World Bank.