In an unprecedented feat, a Japanese consortium has not only built the world’s longest transmission link, but also successfully tested it by transmitting a large quantity of data using it. The consortium comprises the National Institute of Informatics (NII), Nippon Telegraph and Telephone Corporation (NTT), Nippon Telegraph and Telephone East Corporation (NTT EAST), and Fujitsu Limited.
According to a joint statement issued by them, they have constructed the world’s longest transmission link at 1.2 Tbps per optical wavelength and succeeded in full throughput transmission and the world’s largest capacity data transfer over 1 Tbps using a pair of general-purpose 1-socket servers on October 17, 2023.
“This field trial was conducted using NTT EAST’s commercial optical fiber, NTT’s digital signal processing technology and devices, Fujitsu’s next-generation optical transmission system 1FINITY Ultra Optical System, and Massively Multi-Connection File Transfer Protocol (MMCFTP *Note1), a file transfer protocol developed by NII,” they said, adding, “This achievement opens the door to a variety of high-speed, high-capacity communication services, including academic communication networks, while simultaneously contributing to lower costs and lower power consumption.”
NII is an academic research institute dedicated to informatics. It conducts both long-term basic research and practical research aimed at solving social problems in a wide range of informatics research fields, from fundamental theories to the latest topics, such as artificial intelligence, big data, the Internet of Things (IoT), and information security.
The research group will use this achievement to further advance academic communication networks and promote research and development toward the realization of the Innovative Optical and Wireless Network (IOWN). According to the statement, “Since April 2022, for example, NII has been operating SINET6, an academic information network connecting all prefectures in Japan with 400 Gbps lines excluding Okinawa connecting with 200G. SINET6 also connects Japan and the United States with 200 Gbps lines. However, demand for SINET6 has been rapidly increasing, for example, transferring data is approaching 400 Gbps, and as access lines for universities and research institutions have become faster (currently 15 lines of 400 Gbps, 88 lines of 100 Gbps, 884 lines of 10 Gbps, etc.). Thus, further capacity expansion is desired to reach over 400 Gbps.”
Meanwhile, NTT aims to realize the All-Photonics Network (APN) under the IOWN initiative by around 2030. NTT also aims to increase the transmission capacity by 125 times by introducing photonics-based technology at APN to realize overwhelmingly low power consumption, high quality, high capacity, and low delay transmission that is difficult with current electronics-based technology. To achieve these goals, NII is working on high-throughput file transfer technology that maximizes the use of high-capacity circuits. Fujitsu and NTT are also developing digital coherent signal processing circuits and photoelectric fusion devices that can deliver the world’s largest capacity optical transmission of 1.2 Tbps per optical wavelength, as well as optical transmission systems.
How did they do it?
According to the consortium, in October 2023, the research group constructed an optical transmission network environment capable of transmitting 1.2 Tbps per optical wavelength between Tokyo and Kanagawa Prefecture in Japan and conducted 2 types of field trials.
In the first trial, they constructed a network that starts in Chiyoda-ku, Tokyo and an optical fiber turns around in Yokohama, Kanagawa Prefecture, and confirmed that transmission of 1.2 Tbps per optical wavelength is possible. This is the first time in the world that an optical signal of 1.2 Tbps per optical wavelength has been transmitted over 336 km using commercial optical fiber.
In the second trial, the research group transferred data using MMCFTP using NII’s a pair of general-purpose 1-socket servers in an environment that transmits 1.2 Tbps. As a result of the trial, a large capacity data of about 47 TBytes was successfully transferred at a data transfer rate of 1,034 Gbps.
For context, at a data transfer rate of 1034 Gbps, one Blu-ray disk with a typical capacity of 25 GBytes can be transferred in about 0.2 seconds. 47 TBytes of data is roughly equivalent to that contained in 1,880 Blu-ray discs can be transferred in approximately 376 seconds. More details about the field trials may be read here.
