Nokia Bell Labs announces record single-carrier bit rate of 1.52 Tbit/s over 80 km of standard single-mode fiber

March 13, 2020
Nokia Bell Labs researchers also trialled spatial-division-multiplexed (SDM) cable over a 2000 km span of 4-core coupled-core fiber, among other things.

Nokia Bell Labs (Murray Hill, NJ) says that its researchers have set the world record for the highest single-carrier bit rate at 1.52 Tbit/s over 80 km of standard single mode fiber, which is four times the market's current state-of-the-art rate of approximately 400 Gbit/s. The company also announced other achievements.

Several of the achievements were presented as part of Nokia Bell Labs’ post-deadline research papers at the Optical Fiber Communications Conference & Exhibition (OFC) held March 8 to 12, 2020 in San Diego. Additionally, Nokia Bell Labs researcher Di Che was awarded the OFC Tingye Li Innovation Prize. Named after the late Tingye Li, a Bell Labs luminary in the field of optical communications, the prize is given to an early career professional who has demonstrated innovation in their research.

The highest single-carrier bit rate at 1.52 Tbit/s was set by a Nokia Bell Labs optical research team led by Fred Buchali. This record was established by employing a new 128 Gigasample/s converter enabling the generation of signals at 128 Gbaud symbol rate and information rates of the individual symbols beyond 6.0 bits/symbol/polarization. This accomplishment breaks the team's own record of 1.3 Tbit/s set in September 2019 while supporting Nokia's field trial with Etisalat.

Nokia Bell Labs researcher Di Che and team also set a new data-rate world record for directly modulated lasers (DMLs), which are important for low-cost, high-speed applications such as datacenter connections. The DML team achieved a record data rate beyond 400 Gbit/s for links up to 15 km.

Other achievements in optical communications announced by Nokia Bell Lab include:

--The first field trial using spatial-division-multiplexed (SDM) cable over a 2000 km span of 4-core coupled-core fiber was achieved by researchers Roland Ryf and the SDM team. The experiments show that coupled-core fibers are technically viable and offer high transmission performance, while rentaining the industry standard 125-μm cladding diameter.

--A research team led by Rene-Jean Essiambre, Roland Ryf, and Murali Kodialam introduced a novel set of modulation formats that provide improved linear and nonlinear transmission performance at submarine distances of 10,000 km. The proposed transmission formats are generated by a neuronal network and can significantly outperform traditional formats (QPSK) used in today's submarine systems.

--Researcher Junho Cho and team experimentally demonstrated capacity gains of 23% for submarine cable systems that operate under electrical supply power constraints. The capacity gains were achieved by optimizing the gain shaping filters using neural networks.

The researchers that achieved the world record and research results are part of Nokia Bell Labs' Smart Optical Fabric & Devices Research Lab, which designs and builds future optical communications systems, "pushing the state-of-the-art in physics, materials science, math, software, and optics to create new networks that adapt to changing conditions and go far beyond today's limitations," according to Nokia Bell Labs.

Nokia Bell Labs is the industrial research arm of Nokia. It is the same Bell Labs that over its 90-year history has invented many of the foundational technologies that underpin information and communications networks, and digital devices and systems. For more info, see www.bell-labs.com.

Source: Nokia Bell Labs


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About the Author

John Wallace | Senior Technical Editor (1998-2022)

John Wallace was with Laser Focus World for nearly 25 years, retiring in late June 2022. He obtained a bachelor's degree in mechanical engineering and physics at Rutgers University and a master's in optical engineering at the University of Rochester. Before becoming an editor, John worked as an engineer at RCA, Exxon, Eastman Kodak, and GCA Corporation.

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