Plastic Fiber Revolution: Keio University’s Breakthrough Could Power the Future of AI Data Centers
In the race to build faster, smarter, and more energy-efficient AI data centers, a surprising new contender has emerged—not silicon, not glass, but plastic.
A pioneering team of researchers at Keio University in Japan has unveiled a groundbreaking plastic optical fiber (POF) technology that could radically transform short-range, high-speed communication within next-generation data centers. This innovation, which blends cutting-edge photonics with practical scalability, promises to break through the communication bottlenecks currently throttling the performance of AI systems.
Announced ahead of the prestigious Optical Fiber Communication Conference (OFC) 2025, the team’s invention—a multicore graded-index POF capable of transmitting data at an astonishing 106.25 Gbps per core—is poised to redefine how data moves across dense computing architectures.
At the heart of this achievement is a simple yet profound goal: create a faster, more scalable backbone for AI infrastructure.
Rethinking the Fiber of Our Digital World
Today’s AI workloads are powered by thousands of high-performance GPUs and accelerators, all of which must exchange enormous volumes of data in real time. Traditional interconnects—especially those relying on glass-based optical fibers—struggle with cost, complexity, and physical limitations, especially as AI systems scale to ever-larger clusters.
Enter plastic optical fiber—a long-overlooked medium now reimagined by Professor Yasuhiro Koike and Lecturer Kenta Muramoto of the Keio Photonics Research Institute. Unlike conventional glass fibers that require complex manufacturing processes involving ribbonization and custom multicore connectors, the Keio team’s approach enables one-step fabrication of multicore POFs through extrusion molding.
This manufacturing breakthrough doesn’t just simplify production—it slashes cost and complexity by a factor of 10 to 100. Just as importantly, it offers the flexibility to scale: no matter how many cores or how they're arranged, these fibers can be mass-produced efficiently, supporting a wide range of data center layouts and designs.
Speed Meets Stability
Technical excellence is where this innovation truly shines. In performance testing, the team’s multicore POF maintained exceptional signal integrity even after transmitting 106.25Gbps PAM4 signals over 30 meters. That’s no small feat in the fiber optics world, where longer distances often result in distorted or degraded signals.
But Keio’s plastic fiber seems to turn conventional wisdom on its head. Thanks to the fiber’s graded-index (GI) structure—a subtle variation in refractive index across the core—light signals naturally refocus as they travel, minimizing dispersion and maintaining clarity.
Even more remarkable is the fine-grained internal architecture embedded within each core. “GI-type POF has a property in which the fine non-uniform structure formed inside the core reduces the coherence of light,” the team explained. This unique structure acts as a volumetric noise reduction mechanism, diffusing optical coherence and reducing interference across the entire fiber.
The result? Bit error rates (BER) were reduced by 1/10,000 to 1/100,000 compared to conventional glass fibers—a dramatic improvement in data reliability and efficiency.
Scalable Designs, Real-World Impact
The team didn’t stop at the lab bench. They successfully produced and tested multiple variants of their multicore GI-POF, including a 61-core circular version and a 4-core rectangular variant. Both showed stable, high-fidelity signal transmission across all cores, proving that the technology is not just theoretically promising—it’s practically viable.
When paired with VCSELs (vertical-cavity surface-emitting lasers)—a common light source in high-speed data links—the fibers delivered sustained performance with no significant degradation over standard data center interconnect lengths.
And this is just the beginning.
Two technical papers detailing the research have been accepted at OFC 2025, a strong vote of confidence from the global photonics community. As cloud providers, AI companies, and semiconductor firms look for better ways to connect the ever-growing webs of processors in their data centers, Keio’s innovation could offer exactly what the industry needs: high-performance, cost-effective, and scalable optical links that keep pace with AI’s insatiable demand for data.
Lighting the Path Ahead
The implications of Keio University’s plastic optical fiber technology stretch far beyond a single data center or use case. It represents a fundamental shift in how we think about optical communication in environments that demand ultra-low latency, high bandwidth, and adaptable deployment.
It’s not just about speed—it’s about democratizing high-speed connectivity. With lower production costs and easier installation, this technology could enable smaller organizations and startups to build AI infrastructure that previously required massive capital and technical expertise.
In the words of the researchers, this is a solution born not only of engineering ingenuity but of visionary design: reimagining the very medium through which data flows to meet the demands of an AI-driven future.
As AI continues to evolve, transforming fields from healthcare to climate science to robotics, the invisible threads connecting those systems must evolve too. Thanks to Keio University’s visionary team, those threads may soon be made of plastic—but with the power to carry a world of intelligence.
This article contains AI generated content using information from these sources:
TechRadar.com - https://www.techradar.com/pro/glass-out-plastic-in-new-fiber-optic-technology-set-to-be-deployed-in-ai-data-centers-is-both-cheaper-and-faster
