Why it matters: A technological leap in fiber optics has shattered previous limitations, achieving what experts once considered impossible: transmitting data at 1.02 petabits per second – enough to download every movie on Netflix 30 times over – across 1,808 kilometers using a single fiber no thicker than a human hair. At the heart of this breakthrough – driven by Japan's National Institute of Information and Communications Technology (NICT) and Sumitomo Electric Industries – is a 19-core optical fiber with a standard 0.125 mm cladding diameter, designed to fit seamlessly into existing infrastructure and eliminate the need for costly upgrades. Each core acts as an independent data channel, collectively forming a "19-lane highway" within the same space as traditional single-core fibers. Unlike earlier multi-core designs limited to short distances or specialized wavelength bands, this fiber operates efficiently across the C and L bands (commercial standards used globally) thanks to a refined core arrangement that slashes signal loss by 40% compared to prior models. The experiment's success relied on a complex recirculating loop system. Signals traveled through an 86.1-kilometer fiber segment 21 times, simulating a cross-continental journey equivalent to linking Berlin to Naples or Sapporo to Fukuoka. To maintain integrity over this distance, researchers deployed a dual-band optical amplification system, comprising separate devices that boosted signals in the C and L bands. This enabled 180 distinct wavelengths to carry data simultaneously using 16QAM modulation, a method that packs more information into each pulse. // Related Stories At the receiving end, a 19-channel detector, paired with advanced MIMO (multiple-input multiple-output) processing, dissected interference between cores, much like untangling 19 overlapping conversations in a crowded room. Schematic diagram of the transmission system This digital signal processor, leveraging algorithms developed over a decade of multi-core research, extracted usable data at unprecedented rates while correcting for distortions accumulated over 1,808 km. The achievement caps years of incremental progress. In 2023, the same team achieved 1.7 petabits per second, but only across 63.5 km. Earlier efforts using 4-core fibers reached 0.138 petabits over 12,345 km by tapping the less practical S-band, while 15-mode fibers struggled with signal distortion beyond 1,001 km due to mismatched propagation characteristics. The new 19-core fiber's uniform core design sidesteps these issues, achieving a capacity-distance product of 1.86 exabits per second per kilometer – 14 times higher than previous records for standard fibers. Image diagram of 19-core optical fiber. Presented as the top-rated post-deadline paper at OFC 2025 in San Francisco, this work arrives as global data traffic is projected to triple by 2030. While challenges remain, such as optimizing amplifier efficiency and scaling MIMO processing for real-world use, the technology offers a viable path to petabit-scale networks. Researchers aim to refine production techniques for mass deployment, potentially enabling transoceanic cables that move entire data centers' worth of information hourly. Researchers aim to refine production techniques for mass deployment, potentially enabling transoceanic cables that move entire data centers' worth of information hourly. Sumitomo Electric's engineers, who designed the fiber's coupled-core architecture, note that existing manufacturing lines can adapt to produce the 19-core design with minimal retooling. Meanwhile, NICT's team is exploring AI-driven signal processing to further boost speeds. As 6G and quantum computing loom, this breakthrough positions fiber optics not just as a backbone for tomorrow's internet, but as the central nervous system of a hyperconnected planetary infrastructure.

Editor's take: The University of Arizona could become the birthplace of the world's first petahertz-speed transistor. If successful, this research work could mark the dawn of a new era in computing, where the speed of light, rather than electricity, sets the pace for innovation. A team of scientists has unveiled a breakthrough that could one day propel computers to operate at speeds millions of times faster than today's most advanced processors. The discovery, led by researchers at the University of Arizona and their international collaborators, centers on harnessing ultrafast pulses of light to control the movement of electrons in graphene – a material just one atom thick. The research, recently published in Nature Communications, demonstrates that electrons can be made to bypass barriers almost instantaneously by firing laser pulses lasting less than a trillionth of a second at graphene. This phenomenon, known as quantum tunneling, has long intrigued physicists, but the team's ability to observe and manipulate it in real time marks a significant milestone. Mohammed Hassan, an associate professor of physics and optical sciences at the University of Arizona, explained that this advance could usher in processing speeds in the petahertz range – over a thousand times faster than the chips powering today's computers. Such a leap, he said, would transform the landscape of computing, enabling dramatic progress in fields ranging from artificial intelligence and space research to chemistry and health care. Hassan, who previously led the development of the world's fastest electron microscope, worked alongside colleagues from the University of Arizona, the California Institute of Technology's Jet Propulsion Laboratory, and Ludwig Maximilian University of Munich. Their initial focus was studying how graphene conducts electricity when exposed to laser light. Typically, the symmetrical structure of graphene causes the currents generated on either side to cancel each other out, resulting in no net current. However, the team made a surprising discovery after modifying the graphene samples. They observed that a single electron could "tunnel" through the material – and that this fleeting event could be captured in real time. This unexpected result prompted further investigation and ultimately led to the creation of what Hassan calls "the world's fastest petahertz quantum transistor." // Related Stories To achieve this, the scientists used a commercially available graphene phototransistor, enhanced with a special silicon layer. They exposed it to a laser switching on and off at an astonishing rate of 638 attoseconds – each attosecond being one quintillionth of a second. The result was a transistor capable of operating at petahertz speeds, a feat previously considered far beyond reach. Unlike many scientific breakthroughs that require highly controlled laboratory environments, this new transistor functioned in everyday, ambient conditions. This opens the door for the technology to be adapted for commercial use and integrated into future generations of electronic devices. Hassan and his team are now working with Tech Launch Arizona to patent and commercialize their invention. Their next goal is to develop a version of the transistor that operates using standard, commercially available lasers, making the technology more accessible to industry partners.