We demonstrate a bright fibre source of heralded single photons at 1550 nm with detected rates greater than 10 kilocounts per second. Photon generation and separation is performed in spliced fibre components.
We have developed a source of time-correlated photon pairs based on phase matched four-wave mixing in a photonic crystal fiber designed to have a zero dispersion wavelength, lambda0, close to 715nm. We generate parametric gain by pumping close to lambda0in the normal dispersion regime. By pumping with a pulsed titanium-sapphire (TI-SA) laser tuned to 708 nm we generate pair-photons at 583 nm and 900 nm visible to efficient silicon- based photon counting detectors. We can generate >100000 detected pairs per second (in a single spatial and temoral mode) with a few milli-watts of pump power. Using this source we have been able to show high visibility multi-photon interference, by mixing at a 50:50 beam-splitter, two heralded single photons generated in spatially separated micro-structured fibres. The source brightness meant we were able to measure high rates of four- photon generation and detection.
An all-fibre heralded single photon source operating at 1570 nm has been demonstrated. The device generates correlated photon pairs, widely spaced in frequency, through four-wave mixing in a photonic crystal fibre. Separation of the pair photons and narrowband filtering is all achieved in fibre. The output heralded single photon rate was 9.2 x 10(4) per second, with a counts-to-accidentals ratio of 10.4 and a heralding fidelity of 52 %. Furthermore, narrowband filtering ensured that the output single photon state was near time-bandwidth limited with a coherence length of 4 ps. Such a source is well suited to quantum information processing applications.