Generation of correlated photons via four-wave mixing in optical fibres

Correlated photons have been used in quantum optics for the generation of s queezed light, demonstration of quantum interference effects, quantum crypt ography, Einstein-Podolsky-Rosen experiments and most recently, quantum tel eportation. Usually, they are generated using chi ((2)) parametric processe s to take advantage of large chi ((2)) nonlinearities and to wavelength sep arate the correlated photons from the pump photons. Here, we examine the ge neration of correlated photons using chi ((3)) parametric processes in opti cal fibres. We show that using such processes provides a simple and inexpen sive correlated photon source readily compatible with communications techno logies.