Researchers Shatter Bandwidth Record Using Existing 4-Core Fiber Cables

Researchers at the National Institute of Information and Communications Technology (NICT) in Japan have achieved greater than 1 Petabit per second (Pb/s) data transfers using 4-core fiber with standard cladding. The key advance, facilitating this new transfer speed record, is the transmission system's support for optical bandwidth exceeding 20 THz. This beefy bandwidth comes largely thanks to the application of wavelength division multiplexing (WDM) technology and the deployment of the experimental S-band.

According to the NICT researchers, with this amount of bandwidth on tap you could broadcast 10 million 8K TV channels simultaneously.

One of the most important aspects of the headlining advance, achieving 1.02 Pbps data transfers, is that the cables used were compatible with existing infrastructure. Adhering to this specification, the technology will be able to be deployed in high-throughput and long-distance links sooner rather than later.

Previous attempts at high-data-rate transfers using the same optical fiber cabling, 125μm diameter 4-core MCF (Multi Core Fiber), peaked at 0.61 Pbps in tests by the same researchers back in March 2020. Now that greater than 1 Pbps transfers have been achieved with 4-core MCF, the research team can claim performance parity with more advanced 15-core fiber.

The push up from 0.61 to 1.02 Pb/s is mostly due to WDM technology. 'M' in this acronym stands for multiplexing, and record optical bandwidth exceeding 20 THz was achieved after multiplexing the already commercially adopted C- and L-transmission bands with recently explored S-band technology. 

"Two kinds of doped fiber amplifiers along with Raman amplification with pumps added in a novel multi-core pump combiner, enabled transmission of 801 wavelength channels over the 20 THz optical bandwidth," explains the academic post.

The diagram above shows a summary of how the impressive bandwidth was achieved. Throughput is plotted against the wavelengths exploited – in 801 channels with 25 GHz spacing for high spectral density.

In the diagram above we get a hint regarding the next step by NICT. Every time the researchers achieve a high data rate transfer milestone, they appear to follow up with work on a long-distance optimized fiber transmission technique. Thus we would expect, with some degree of confidence, that the 4-core MCF long-distance data rate record of 0.32 Pb/s (distance between 2,000 and 3,000km) will be broken in the coming months.