Patent ID: 7826749

Claim:
A method of quantum key distribution between a transmitter and a plurality of receivers over a wavelength division multiplexing (WDM) network, comprising: assigning a different receiving-wavelength to each of the plurality of receivers, respectively; selecting a receiver from the receivers to be communicated with the transmitter, wherein each of the plurality of receivers comprises an interferometer; and transmitting quantum signals from the transmitter to the selected receiver over the WDM network, wherein the transmitted quantum signals are at a wavelength equal to the receiving-wavelength of the receiver, and wherein transmitting quantum signals from the transmitter to the selected receiver over the WDM network comprises: emitting a light from a source of the transmitter, wherein the light emitted from the source is a continuous-wave light; randomly phase-modulating the continuous-wave light with at least two non-orthogonal states at a phase modulation period; attenuating the phase-modulated continuous-wave light such that an average photon number of the light less than one is detected within a time slot by a single photon detector; and transmitting the attenuated light through an optical fiber, wherein the optical fiber is optically coupled to the interferometer of the selected receiver via a wavelength division demultiplexer.