Optimised domain-engineered crystals for pure telecom photon sources

Alexander Pickston*, Francesco Graffitti, Peter Barrow, Christopher L. Morrison, Joseph Ho, Agata M. Brańczyk, Alessandro Fedrizzi

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

26 Citations (Scopus)
79 Downloads (Pure)


The ideal photon-pair source for building up multi-qubit states needs to produce indistinguishable photons with high efficiency. Indistinguishability is crucial for minimising errors in two-photon interference, central to building larger states, while high heralding rates will be needed to overcome unfavourable loss scaling. Domain engineering in parametric down-conversion sources negates the need for lossy spectral filtering allowing one to satisfy these conditions inherently within the source design. Here, we present a telecom-wavelength parametric down-conversion photon source that operates on the achievable limit of domain engineering. We generate photons from independent sources which achieve two-photon interference visibilities of up to 98.6 ± 1.1% without narrow-band filtering. As a consequence, we reach net heralding efficiencies of up to 67.5%, which corresponds to collection efficiencies exceeding 90%.

Original languageEnglish
Pages (from-to)6991-7002
Number of pages12
JournalOptics Express
Issue number5
Early online date19 Feb 2021
Publication statusPublished - 1 Mar 2021

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics


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