Soitec wins from Google's TPUv8i regardless of which foundry builds the chips, because it supplies the photonics-SOI wafers upstream. TPUv8i's silicon-photonics optical circuit switch adds a new layer of large photonic dies, and its signal loss forces transceivers to go coherent, using about 2-2.5x more silicon per port and roughly 3-4x the wafer starts. Risks include coherent modulators moving to indium phosphide or thin-film lithium niobate, and Marvell building its own photonics. x.com
