New Nokia modulation format breaks subsea fiber-optic transmission records
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."
Gail Overton | Senior Editor (2004-2020)
Gail has more than 30 years of engineering, marketing, product management, and editorial experience in the photonics and optical communications industry. Before joining the staff at Laser Focus World in 2004, she held many product management and product marketing roles in the fiber-optics industry, most notably at Hughes (El Segundo, CA), GTE Labs (Waltham, MA), Corning (Corning, NY), Photon Kinetics (Beaverton, OR), and Newport Corporation (Irvine, CA). During her marketing career, Gail published articles in WDM Solutions and Sensors magazine and traveled internationally to conduct product and sales training. Gail received her BS degree in physics, with an emphasis in optics, from San Diego State University in San Diego, CA in May 1986.