Non-classical photon streams using rephased amplified spontaneous emission: The role of inhomogeneous broadening in DLCZ schemes

We present a fully quantum mechanical treatment of optically rephased photon echoes. These echoes exhibit are noisy due to amplified spontaneous emission, however this noise can be seen as a consequence of the entanglement between the atoms and the output light. With a rephasing pulse one can get an" echo" of the amplified spontaneous emission, leading to light with nonclassical correlations at points separated in time, which is of interest in the context of building wide bandwith quantum repeaters. We also suggest a wideband version of DLCZ protocol based on the same ideas.