Ultra-fast co-packaged optical wireless link for wireless-assisted data center interconnection

Abstract As AI data centers scale rapidly in throughput and size, the deployment and management complexity of fiber-connected interconnects is becoming a key bottleneck. Optical wireless communication (OWC) offers a flexible alternative to cabled interconnects, yet its per-channel data rates have historically lagged behind those of wired counterparts due to limited electro-optic bandwidth and front-end distortions. In this work, we narrow this gap through end-to-end co-design of the transceiver front ends, packaging interfaces, and nonlinear equalization algorithms, which together shape an effectively wideband, controlled-impedance electrical channel. Guided by systematic interface modeling, the proposed co-packaged solution eliminates the impedance discontinuity via dedicated transmission line design and an inductance-reduced bond-wire scheme, effectively extending the analog bandwidth while suppressing resonant peaking. To further mitigate residual level-dependent nonlinear intersymbol interference (ISI), an offline third-order Volterra-series nonlinear equalizer (VNE) is employed. Leveraging this hardware–algorithm synergy, we experimentally demonstrate a four-channel transceiver module that achieves record-high 100 Gb/s NRZ and 160 Gb/s PAM-4 per channel (640 Gb/s aggregate) over a 50 cm free-space link. To the best of our knowledge, this is the first multi-channel intensity-modulation and direct-detection (IM/DD) OWC system to attain wired-class performance, providing a scalable pathway for deploying high-speed OWC in next-generation data centers.