Ultra-high bandwidth-density integrated coherent optics (Conference Presentation)

Next-generation computing clusters demand ultra-high-bandwidth optical interconnects for large-scale AI applications, necessitating densely integrated high-speed electro-optical converters. Coherent optics, known for its extreme transmission capacity, is gaining attention for intra-data-center interconnects due to its enhanced receiver sensitivity, crucial for next-generation transceivers. However, integrated coherent transceivers still lag behind IM-DD counterparts in bandwidth density and energy efficiency, mainly due to challenges in compact modulator design. Leveraging ultra-fast coherent dynamics, we designed and experimentally demonstrated a series of ultra-compact, ultra-wide-bandwidth coherent modulators on silicon chips, fabricated with CMOS-compatible photonic processes. These designs achieved a record on-chip shoreline bandwidth density reaching multi-Tb/s/mm, with a net bit rate over 1 Tb/s across tens of kilometers.