Co-Packaged Optics for the AI Era

Scaling of AI workloads has transformed computing into a fundamentally communication limited system, exposing hard limits in power delivery, bandwidth density and network scalability. As “AI factories” push toward hundreds of thousands of accelerators, legacy assumptions about high-speed signal reach, pluggable optics, and modular system boundaries are being aggressively challenged. CoPackaged Optics (CPO) is not an incremental optical upgrade-it represents an architectural inflection point driven by the economics of scale itself.

This talk examines why the marketplace for CPO is accelerating, and argues that its success is increasingly enabled by advanced packaging technologies rather than optical device physics alone. A diverse set of optical platforms—including VCSELs, silicon photonics, and indium phosphide photonics-are likely to coexist within AI datacenters as context specific solutions optimized across coupled dimensions of reach, bandwidth density, energy per bit, thermal tolerance, fiber count, reliability, cost, and package form factor.

Crucially, the evolution of CPO is inseparable from the adoption of microelectronics packaging concepts such as chiplet architectures, fanout wafer level packaging, hybrid integration, high density interposers, and waferscale integration. Parallel photonics optimized packaging concepts are also emerging. Selected IBM Research innovations, including polymer waveguide based adiabatic coupling, will be discussed as enablers for bandwidth dense, robust, and manufacturable CPO systems.