Generation of photon pairs with tailored spectral properties by spontaneous four-wave mixing

We present a theoretical study of the generation of photon pairs by spontaneous four-wave mixing (SFWM) in photonic crystal optical fiber. We show that it is possible to engineer two-photon states with specific spectral entanglement properties suitable for quantum information processing applications. In this work, we concentrate on states exhibiting no spectral correlations in the two-photon component of the state, which allow heralding of pure-state, single-photon wavepackets without the need for spectral post filtering. We present specific source designs which permit both symmetric and asymmetric factorable states, with signal and idler photons in the visible, and sufficiently removed from the pump to ensure suppression of background photons produced by spontaneous Raman scattering.