New Nokia modulation format breaks subsea fiber-optic transmission records

Nokia, in collaboration with Facebook, has used PCS technology to increase fiber-optic capacity by 2.5X

Nokia (Espoo, Finland), in collaboration with Facebook, has used its new probabilistic constellation shaping (PCS) technology in a digital signal processing (DSP) field trial over a 5500 km transatlantic subsea link and demonstrated almost 2.5X more capacity than the stated optical transmission capacity of the system.

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The new Nokia Bell Labs research PCS modulation format uses 'shaped' quadrature amplitude modulation (QAM) formats to flexibly adjust transmission capacity to near the physical limits of a given fiber-optic link. In this first-of-its-kind experiment for an installed submarine link, conceived and planned by Facebook, PCS based on 64 QAM, combined with digital nonlinearity compensation and low-linewidth lasers, achieved a record spectral efficiency of 7.46 b/s/Hz, indicating the potential to upgrade this cable to 32 Tb/s per fiber in the future.

Transmission tests based on the commercially available Nokia Photonic Service Engine 2 (PSE-2) validated the successful transmission of 8-QAM wavelengths.

Stephen Grubb, global optical network architect at Facebook, said,"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."

SOURCE: Nokia; http://www.nokia.com/en_int/news/releases/2017/03/21/nokia-and-facebook-break-subsea-spectral-efficiency-records-in-transatlantic-field-tests

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