Cluster state generation using fibre sources

Pure state single photons are at the heart of optical quantum technologies. We have previously reported the generation of photon pairs by four-wave mixing in a single-mode photonic crystal fibre (PCF) and the use of a new birefringent phase matching scheme which results in the generation of narrowband signal photons, around 0.2 nm in bandwidth, and a factorizable photon pair state with no requirement for spectral filtering, leading to increased count rates. Our source is bright, polarized, and tuneable by variable laser wavelength and fibre parameters. Hong-Ou-Mandel (HOM) interference is observed between photons from two of these sources, a requirement for optical quantum information tasks.