#Japan #Tokyo #Optical Communication #NICT #19-Core Fiber

New Milestone in Optical Fiber Technology

In a remarkable achievement in the field of optical communication, researchers from the National Institute of Information and Communications Technology (NICT) and Sumitomo Electric Industries have successfully transmitted data at an unprecedented speed of 1.02 petabits per second over a distance of 1,808 kilometers. This milestone, equivalent to the distance from Sapporo to Fukuoka, marks a new world record for standard diameter 19-core optical fibers, with a calculated capacity-and-distance product reaching 1.86 exabits per second-kilometer.

Understanding the Technology

The breakthrough was made possible through the development of a 19-core optical fiber of a standard diameter (0.125 mm) combined with a newly designed optical amplification relay function. Previous records showed transmission capabilities exceeding 1 petabit per second; however, none had demonstrated long-distance transmission over 1,000 kilometers. This innovation has significantly contributed to the expanding demand for long-distance, high-capacity optical communication infrastructures needed for the future.

Research Background

To support the escalating need for communication, researchers worldwide are exploring advanced multi-core optical fibers and data transmission systems that exceed traditional limits. Over the years, NICT has demonstrated the potential of various standard diameter optical fibers in long-distance, high-capacity scenarios. For instance, a non-coupled type 4-core optical fiber achieved a remarkable capacity of 0.138 petabits over 12,345 kilometers. However, the limitations of non-coupled multi-core fibers, particularly regarding core number restrictions due to signal interference, led to the current innovation involving the coupled 19-core optical fiber, which successfully reduced losses across multiple wavelength bands (C-band and L-band).

Detailed Transmission System Development

In this project, Sumitomo Electric was pivotal in designing and manufacturing the coupled 19-core optical fiber, optimizing the structure and layout of the cores to enhance signal transmission across different wavelengths. The NICT team focused on developing the transmission system capable of amplifying signals from all 19 cores simultaneously. This complex system involves a sender, receiver, and a loop transmission system made up of fiber optical amplifiers, multiplexers, and switches.

The experimental setup allowed for a staggering generation of optical signals totaling 1.02 petabits per second by combining 180 wavelength, polarization-multiplexed 16QAM signals. For validation, the signals traversed an 86.1 km segment of the 19-core optical fiber in a loop configuration, effectively demonstrating the capability to transmit significant distances necessary for urban connectivity in Japan.

Momentum for Future Growth

As we transition to a post-5G society, explosive growth in data communication is anticipated, necessitating advanced information and communication infrastructure. The results from this research not only poised to enhance capacity but also lay groundwork for long-distance optical communication systems capable of meeting future demands. Going forward, efforts will focus on further optimizing the optical amplification relay technology and improving the speed of MIMO digital signal processing to explore rapid implementation in real-world applications.

Acknowledgment at Global Conferences

The profound implications of this research were recognized at the 48th Optical Fiber Communication Conference (OFC 2025) held in San Francisco, where the findings were awarded the title of the best hot topic paper, culminating in a presentation on April 3, 2025.

In summary, this significant achievement in optical fiber technology not only highlights the concerted efforts of NICT and Sumitomo Electric but also paves the way for next-generation optical communications.

Roles of Participating Organizations

• - NICT: Design and development of the transmission system and experiments.
• - Sumitomo Electric: Design and development of the coupled 19-core optical fiber.