Keio University
A research team at Keio University (President: Kohei Itoh), led by Project Professor Yasuhiro Koike, Director of the Keio Photonics Research Institute (KPRI), and Project Senior Assistant Professor Kenta Muramoto, both at the Keio Frontier Research & Education Collaborative Square (K-FRECS) at Shin-Kawasaki, has developed a graded-index plastic optical fiber (GI POF) for higher-speed short-reach optical interconnects and successfully demonstrated next-generation single-lane transmission at 212.5 Gbps (gigabits per second) over 50 meters.
With the proliferation of generative AI, the volume of data exchanged within data centers is growing, and higher-speed short-reach data links connecting computing devices are increasingly required. Such links commonly use a combination of vertical-cavity surface-emitting lasers (VCSELs) and silica-glass-based multimode optical fibers (MMFs). However, further boosting per-lane data rates toward the 212.5-Gbps class is challenging because transmission bandwidth is constrained by modal dispersion and material dispersion in the optical fiber. In this work, the researchers demonstrated a GI POF that provides transmission bandwidth exceeding that of silica MMF by precisely controlling the refractive-index profile to reduce modal dispersion and by using a perfluorinated polymer with lower material dispersion than silica glass.
These results were accepted and presented at the Optical Fiber Communication Conference (OFC) 2026, one of the world’s largest international conferences in optical communications, as a co-authored paper by KPRI of Keio University and Broadcom Inc.
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