Japan’s National Institute of Information and Communications Technology and Fujikura Claim World Record
Japan’s National Institute of Information and Communications Technology (NICT) Network System Research Institute and Fujikura Ltd have successfully demonstrated a transmission experiment using a three-mode optical fibre over 1,045 km with a data rate of 159 Tbits/s. The optical fibre, developed by Fujikura, is capable of wideband wavelength multiplexing transmission and has a standard outer diameter of 0.125 mm, enabling it to be cabled with existing equipment.
The researchers note that multimode fibres have different propagation delays between optical signals in different modes that make it difficult to simultaneously satisfy large data rates and long distance transmission. The new demonstration shows it is possible to overcome such limitations.
Converting the demonstration’s results to the product of data rate and distance, which is a general indicator of transmission capability, results in 166 Pbits/s × km. According to the partners, this is the world record in a standard outer diameter few-mode optical fibre, and the largest data rate over 1,000 km for any kind of standard diameter fibre.
In order to achieve the transmission capacity of 159 Tbits/s, mode multiplexing was used in combination with 16-QAM, which is a practical high-density multilevel modulation optical signal, for all 348 wavelengths. Multiple-Input and Multiple-Output (MIMO) enabled unscrambling of mixed modal signals, even after transmission over more than 1,000 km. This shows that standard outer diameter multimode fibres can be used for communication of high capacity optical backbone transmission systems.
In a statement, the researchers observe that when laying of standard outer diameter optical fibres takes place, existing equipment can be used and that the practical use of this at an early stage is promising. Also, ultimate large-capacity transmission will become possible in the future if combined with multicore technology, which is being researched by NICT in cooperation with industry, universities and government in Japan.
For the future, NICT and Fujikura say they will continue to research and develop future optical communication infrastructure technologies which can smoothly accommodate traffic such as big data and 5G network services.