Integrated photonics is a powerful contender in the race for a fault-tolerant quantum computer, claiming to be a platform capable of scaling to the necessary number of qubits. This necessitates the use of high-quality quantum states, which we create here using an all-around high-performing photon source on an integrated photonics platform. We use a photonic molecule architecture and broadband directional couplers to protect against fabrication tolerances and ensure reliable operation. As a result, we simultaneously measure a spectral purity of 99.1±0.1 %, a pair generation rate of 4.4±0.1 MHz mW−2, and an intrinsic source heralding efficiency of 94.0±2.9 %. We also see a maximum coincidence-to-accidental ratio of 1644±263. We claim over an order of magnitude improvement in the trivariate trade-off between source heralding efficiency, purity and brightness. Future implementations of the source could achieve in excess of 99 % purity and heralding efficiency using state-of-the-art propagation losses.
@article{arxiv.2303.17258,
title = {Integrate and scale: A source of spectrally separable photon pairs},
author = {Ben M. Burridge and Imad I. Faruque and John G. Rarity and Jorge Barreto},
journal= {arXiv preprint arXiv:2303.17258},
year = {2023}
}