VCSEL-Based Photonics for NVIDIA's Multi-Die GPUs

The performance improvements achievable through technology-node scaling are approaching their practical limits. To further increase the number of transistors, future GPU and CPU performance will increasingly depend on integrating multiple dies or chips within a system. Therefore, die-to-die and chip-to-chip interconnects will become a key technology for future GPUs and CPUs. Conventional electrical interconnects, however, impose practical limits on the number of dies that can be integrated. This article shows that VCSEL-based photonic interconnects can overcome these limitations, not only enabling the integration of a much larger number of dies but also keeping chip-edge width, device area, and total optical loss within practical limits.. The analysis indicates that VCSEL-based photonic interconnects provide a uniquely suitable and scalable solution for future multi-die GPU and CPU architectures.