The National Key Laboratory of Optical Communication Technologies and Networks under China Information and Communication Technologies Group (China InfoComm) recently joined forces with Peng Cheng Laboratory and FiberHome Fujikura Optical Fiber Technology Co., Ltd. to successfully complete a 3.2 Pb/s (petabits per second) multi-core fiber real-time bidirectional transmission trial, setting a world record for bidirectional real-time optical transmission capacity on a single fiber.
"A transmission rate of 3.2 Pb/s means more than 20,000 4K movies can be downloaded in one second," said Yang Chao, a senior engineer of optical systems at the National Key Laboratory of Optical Communication Technologies and Networks under China InfoComm. He noted that the scheme validates the industrialization potential of the ultra-broadband capacity expansion pathway based on multi-core fiber, providing core technology support for next-generation high-speed optical communications in large-scale computing hub interconnection, backbone transmission and 6G bearer networks.
With the large-scale development of artificial intelligence, large-model computing and data centers, network traffic is growing explosively, and traditional single-mode fiber transmission systems are gradually approaching their capacity limits. To address this bottleneck, the team innovatively proposed a 24-core multi-core fiber bidirectional transmission architecture, using a 10.3-kilometer 24-core multi-core fiber and integrating S+C+L three-band multiplexing with space-division multiplexing technologies to build thousands of parallel transmission channels, substantially breaking through the capacity ceiling of traditional single-mode fiber with a greatly expanded total bandwidth. The system is equipped with commercial coherent optical modules and adopts high-order probabilistic shaping modulation to achieve stable real-time bidirectional signal transmission; through optimized core layout, inter-core crosstalk is effectively suppressed, signal equalization processing is simplified, and both transmission performance and engineering practicality are balanced.
"Compared with the capacity ceiling of approximately 100 Tb/s for traditional C+L band commercial single-core G.652 fiber, this system increases the total transmission capacity of a single fiber by 32 times; it has completed real-time transmission verification of self-developed optical modules with 400G per wavelength in the S band and 1.2 Tb/s (terabits per second) per wavelength in the C+L band, breaking through the single-core fiber capacity wall that is difficult to overcome by spectral expansion alone," Yang Chao introduced.
At present, the results have been submitted as an invited paper to the internationally authoritative optics journal Journal of Lightwave Technology.