Framework for quantum modeling of fiber-optical networks: PART I

Abstract

We formulate quantum optics to include frequency dependence in the modeling of optical networks. Entangled light pulses available for quantum cryptography are entangled not only in polarization but also, whether one wants it or not, in frequency. We model effects of the frequency spectrum of faint polarization-entangled light pulses on detection statistics. For instance, we show how polarization entanglement combines with frequency entanglement in the variation of detection statistics with pulse energy. Attention is paid not only to single-photon light states but also to multi-photon states. These are needed (1) to analyze the dependence of statistics on energy and (2) to help in calibrating fiber couplers, lasers and other devices, even when their desired use is for the generation of single-photon light.