Chinese researchers have demonstrated bidirectional data transmission at a speed of 3.2 petabits per second over a single optical fiber, setting a new world record for fiber-optic communication bandwidth. To put this in perspective, more than 20,000 4K resolution movies could be transmitted through such a channel in just one second. The tests were conducted by the China State Key Laboratory of Optical Communication Technologies and Networks (part of the China Information Communication Technologies Group, CICT) in collaboration with the Peng Cheng Laboratory and Fenghuo Fujikura Fiber Optic Technology. The results of the work were submitted to the leading international scientific journal Journal of Lightwave Technology, and the achievement was first reported by Science and Technology Daily.
The "Ceiling" Problem of Single-Mode Fibers
The rapid development of artificial intelligence, the scaling of neural model training, and the growth in the number of data centers have led to an explosive increase in network traffic. Traditional single-mode fiber-optic systems built on the G.652 standard are approaching their capacity limit of around 100 Tbps when operating in the C+L bands. Simply expanding the spectral range is no longer sufficient to significantly overcome this "ceiling," forcing researchers to look for next-generation architectural solutions. It is in this context that an innovative multi-core fiber system was developed.
Architecture of the 24-Core Fiber and Multiplexing
The research team used a 10.3-kilometer segment of 24-core optical fiber, combining multi-band multiplexing in the S+C+L bands with spatial multiplexing across the cores. As a result, thousands of parallel data transmission channels were created, increasing the total capacity of a single fiber by 32 times compared to the limit for a traditional single-core fiber. The system utilizes commercial coherent optical modules and high-order probabilistic shaping modulation methods, ensuring stable real-time bidirectional transmission. According to Yan Chao, a senior optical systems engineer at the laboratory, the per-channel speed reached 400 Gbps in the S-band and 1.2 Tbps in the C+L bands.
Crosstalk Suppression and Industrial Applicability
A key engineering challenge when working with multi-core fiber is suppressing crosstalk between adjacent cores. The developers optimized the spatial arrangement of the cores, which effectively reduced mutual interference and simplified the signal alignment procedure. This approach strikes a balance between maximum transmission performance and the practical suitability of the technology for industrial deployment. According to Yan Chao, the demonstrated solution confirms the industrial potential of multi-core fibers as a means of expanding backbone network bandwidth.
Prospects for 6G Infrastructure and Computing Clusters
A transmission speed of 3.2 Pbps opens up opportunities for interconnecting massive computing centers, building next-generation data backbone networks, and forming 6G communication infrastructure. As the volumes of data generated by artificial intelligence systems and distributed computing clusters continue to grow exponentially, multi-core fiber-optic systems are becoming a critically important element of digital infrastructure. The Chinese achievement, documented in a scientific publication, solidifies the country's position in the race for technological leadership in optical communications and sets a new benchmark for international research in this field.
