Construction of an Integrated Fibre Source of Heralded Single Photons

McMillan, Fulconis, Haider +2 more

Robert J. A. Francis-Jones

Robert J. A. Francis-Jones, Rowan A. Hoggarth, Peter J. Mosley

We present the construction and characterisation of a spatially multiplexed photonic crystal fibre source of high-purity heralded single photons at 1560nm. We demonstrate performance improvements from multiplexing two sources.

Rowan A. Hoggarth, Robert J. A. Francis-Jones, Peter J. Mosley

We present a multiplexed single photon source that re-synchronises heralded single photons generated by four-wave mixing in photonic crystal fibre using a fibre delay loop controlled by a single switch. By combining the probabilities of generating heralded single photons on four consecutive pump pulses we obtain an enhancement of the per-bin single-photon delivery probability. Our source demonstrates a way in which single-photon source multiplexing may be carried out with minimised resource overhead while retaining the benefits of a robust and alignment-free platform.

Robert J. A. Francis-Jones, Rowan A. Hoggarth, Peter J. Mosley

Single photon sources based on spontaneous photon-pair generation have enabled pioneering experiments in quantum optics. However, their non-determinism presents a bottleneck to scaling up photonic and hybrid quantum-enhanced technologies. Furthermore, photon pairs are typically emitted into many correlated frequency modes, producing an undesirable mixed state on heralding. Here we present a complete fibre-integrated heralded single photon source that addresses both these difficulties simultaneously. We use active switching to provide a path to deterministic operation by multiplexing separate spontaneous sources, and dispersion engineering to minimise frequency correlation for high-purity single photon generation. All the essential elements -- nonlinear material with dispersion control, wavelength isolation, optical delay, and fast switching -- are incorporated in a low-loss alignment-free package that heralds photons in telecoms single-mode fibre. Our results demonstrate a scalable approach to delivering pure single photons directly into guided-wave photonic devices.

Robert J. A. Francis-Jones, Peter J. Mosley