Silicon photonics is moving from specialized research into volume production in AI infrastructure and optical communications, and the EDA stack is not keeping up. The existing toolchain handles electronic signals; waveguides, optical phase, wavelength, polarization, and thermal drift require different simulation and verification methods that most commercial EDA flows still treat as add-on, not native.
The mismatch shows up at functional verification. Electronic digital design operates on discrete logic; simulation is deterministic and bounded. Photonic behavior is continuous and physics-dependent: a waveguide's transmission depends on wavelength, polarization, temperature, mechanical stress, and fabrication tolerance simultaneously. Current EDA flows handle EM (HFSS), thermal (Icepak), and analog circuit simulation (SPICE) as separate tool invocations with manual result integration. An electro-optical chip requires running all four simultaneously, and no commercial tool today runs them as a unified co-simulation in a design-loop context. Semiconductor Engineering's reporting identifies functional verification as the biggest unresolved gap: photonic behavior cannot be checked the way digital behavior can, and AI-assisted automation that works on RTL does not transfer to optical waveguide verification.
Chip teams doing silicon photonics tapeouts today are running a fragmented verification workflow: photonic design in Lumerical or OptoDesigner, EM signoff in HFSS, thermal in Icepak, electrical in SPICE, then manually correlating results at tapeout. This is shift-right verification applied to an already expensive process. The teams that build co-simulation into their design loop early (not as a tapeout checklist but as a CI-native check on every major design revision) will catch yield-killing interactions at the geometry stage, not after masks are cut. The EDA vendors that unify these physics domains in a single tool context will consolidate the photonics design-to-tape workflow for the decade of electro-optical scaling that is just starting.