A simple method to characterize a synchronous heralded single photon source

As quantum cryptography and communication continue to develop, the need for true sources of single photon is continuously growing. The production of photon pairs through 2nd and 3rd order non-linear processes in crystals and optical fibre is a simple method for constructing a high quality heralded single photon source (HSPS). The ability to employ such sources for quantum communication depends on the multi-pair statistics of the source, which is conventionally characterized by measuring the second order autocorrelation function, g2(0) with a Hanbury Brown and Twiss (HBT) experimental setup. In practice, a HBT experiment can be difficult to realize, especially when the source is of high quality. We will present a fast and simple method to predict the g2(0) of a HSPS based on nonlinear crystals or optical fibre and show agreement with results from a standard HBT experiment using a PPLN crystal. We will also report on our progress towards repeating the experiment using a microstructured fibre having nonlinear properties tailored to create a HSPS at telecom wavelengths.