A reported switch points to delays in silicon photonics development, with Nvidia's fallback using 16-wavelength DWDM and 200G/400G PAM4 on Tower Semiconductor's platform.
Nvidia has temporarily abandoned TSMC's COUPE technology plan and shifted to a fallback design built on Tower Semiconductor's SiPho (silicon photonics) platform, IrrationAlanalysis reported, citing sources. The reported change was tied to slow progress in TSMC's silicon nitride technology and weaker-than-expected development of 2D grating couplers, key components used to move optical signals efficiently on photonic systems. Nvidia's latest "Plan B" is said to use 16-wavelength DWDM (dense wavelength division multiplexing, sending multiple signals over one fiber) alongside 200G/400G PAM4 (four-level pulse amplitude modulation) to increase optical interconnect capacity.