Energy-efficient optical I/O: develop architecture options for high-density, short-reach optical links relevant to memory-adjacent, scale-up, and disaggregated-compute use cases; compare parallel-emitter arrays, silicon photonics, and emerging emitter / receiver concepts using link-level and packaging-level metrics. Advanced light sources for silicon photonics: evaluate source architectures such as quantum-dot DFB lasers, PIC-enhanced approaches, and comb-based sources against power, wavelength control, integration, reliability, packaging, manufacturability, and platform fit.