Exploring nonlinearity-loss tradeoffs in foundry fabricated silicon integrated photon pair sources

Foundry fabricated silicon heralded photon pair sources underpin a wide range of quantum photonics applications. Traditional photonics foundry platforms, originating in classical datacom applications, have waveguide cross-sections <0.2 μm², which significantly enhance surface absorption and roughness-induced scattering effects on propagating optical fields. Given the critical importance of loss for quantum information applications, here we consider the generation of photon pairs in a low-loss, thick (3 μm) silicon foundry platform and explore the associated nonlinearity-loss-footprint tradeoffs, with a view toward understanding the optimal silicon thickness for resonator-based photon pair sources.