Frequency conversion of single photons in a nonlinear crystal is theoretically discussed. Losses and noise are included within a Heisenberg-Langevin formalism for the propagating photon field. We calculate the first- and second-order correlation functions of the frequency-converted light when the input is a train of single-photon pulses. This model allows one to identify the requirements on the nonlinear device so that it can be integrated in a quantum network.
@article{arxiv.1309.2532,
title = {Single-photon frequency conversion in nonlinear crystals},
author = {Susanne Blum and Georgina A. Olivares-Rentería and Carlo Ottaviani and Christoph Becher and Giovanna Morigi},
journal= {arXiv preprint arXiv:1309.2532},
year = {2013}
}