Silicon modulators are stuck at 3,000–5,000 µm and 60 GHz by the diffraction limit, short of the 3.2T AI needs. Marvell's plasmonic modulator shrinks to ~10 µm, reaches 1 THz, and can be added at the back end of existing SiPh processes. It's a key piece for extending SiPh beyond 3.2T — but volume yield is the real test.