Investigating nonlinearity-loss-footprint tradeoffs in foundry fabricated photon pair sources

Integrated photonics platforms are having an increasing impact in many quantum optical applications, due to their ease of cascading sequential operations while simultaneously scaling to large component numbers. In order to maintain performance fidelity as the complexity of these photonic circuits increases, it is inevitable that these circuits will be implemented with foundry fabrication. Traditional photonics foundry platforms, originating in classical datacom applications, have typical waveguide thickness of 0.22µm, 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 (3µm) 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.