Plastic fiber breakthrough could reshape AI data center performance and cost

Japanese researchers hit 106Gbps per core with plastic fiber breakthrough
Multicore plastic fiber slashes costs and complexity for AI data centers
Bit error rate drops 100,000-fold versus traditional glass-based systems

A team of researchers at Keio University in Japan has developed a breakthrough plastic optical fiber (POF) technology that could transform short-range, high-speed communications in next-generation AI data centers.

Announced ahead of the Optical Fiber Communication Conference (OFC) 2025, the group revealed a multicore graded-index POF capable of transmitting data at up to 106.25Gbps per core.

Led by Professor Yasuhiro Koike and Lecturer Kenta Muramoto at the Keio Photonics Research Institute, the project addresses a growing bottleneck in AI infrastructure: the need for ultra-high-capacity, low-latency interconnects between GPUs and accelerators in dense computing environments.

Faster, more scalable AI infrastructure

Unlike traditional glass fibers, which require complex ribbonization and multicore connectors, the team’s method allows for multicore POFs to be manufactured in one step using extrusion molding. This dramatically reduces costs and complexity, by a factor of 10 to 100, according to the researchers.

The new extrusion technique allows for mass production of multicore fibers regardless of core count or arrangement, making it adaptable to a wide range of data center designs.

Testing confirmed even after 30 meters of transmission at 106.25Gbps PAM4, signal integrity remained high, with minimal degradation in TDECQ. Bit error rates (BER) were reduced by up to 1/10,000 to 1/100,000 compared to conventional glass fibers.

According to the researchers, “GI-type POF has a property in which the fine non-uniform structure formed inside the core reduces the coherence of light, functioning as a volumetric noise reduction effect throughout the entire optical fiber.”

This fine-grained internal structure diffuses optical coherence and acts as a volumetric noise reduction mechanism.

The team’s multicore GI-POF, including a 61-core circular version and a 4-core rectangular variant, reportedly demonstrated high manufacturing reliability and stable transmission across all cores.

Combined with VCSELs (vertical-cavity surface-emitting lasers), the system achieved 106.25Gbps PAM4 signal transmission over 30 meters without significant degradation.

Two papers detailing this work have been accepted at OFC 2025. With increasing demand for efficient, high-performance interconnects, Keio’s multicore plastic fiber technology could be key to unlocking faster, more scalable AI infrastructure in the years ahead.

Via PC Watch

Schematic diagram of mass production of multicore GI-type POF by extrusion molding