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 enhances 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 towards understanding the optimal silicon thickness for resonator based photon pair sources.