TL;DR Nvidia has invested at least $6.5 billion in photonics companies since March 2026, including $2 billion each in Coherent, Lumentum, and Marvell, up to $3.2 billion in Corning, and participation in Ayar Labs’ $500 million Series E. The spending aims to replace copper with light-based interconnects as AI training clusters outgrow electrical bandwidth limits. Nvidia has committed at least $6.5 billion to photonics companies since the beginning of March, making it the largest single investor in the technology that many in the industry believe will replace copper wiring as the backbone of AI data centres. The spending spree reflects a calculation that copper, the standard medium for moving data between chips, is approaching its physical limits just as AI training clusters are demanding exponentially more bandwidth. Photonics uses light rather than electrical signals to transmit data.…