US 12,756,480 B2Granted

Hybrid quantum-classical communication system

AssigneeGeneral Dynamics Mission Systems, Inc.

InventorsClaudia Ann Gamble, Juan C. Juarez, Todd M.W. Hodges, John Anthony Gariano, John M. Liebetreu, Jerry Kwa-Wor Tong

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Abstract

The classical channel employs a transmit laser and classical modulator. The quantum channel employs a nonlinear medium and spontaneous parametric down conversion producing quantum entangled signal and idler photon pairs which are encoded. The classical and quantum channels are combined to define a propagated hybrid signal. The receiver splits the hybrid signal on basis of wavelength into classical and quantum channels. The quantum receiver employs optical parametric amplification, supplied with energy from a second harmonic generation device synchronized to the classical carrier wavelength. A photodetector and extracts a quantum message from the quantum signal.

Claims20

Dependent claims

A hybrid quantum-classical communication system comprising:

a classical channel having:
a transmit laser producing light of first wavelength;
and
a classical modulator producing a classical signal of the first wavelength;
a quantum channel having:
a first nonlinear medium coupled to receive light from the transmit laser and producing a first stream of photons of a wavelength approximately half that of the first wavelength;
a second nonlinear medium receptive of the first stream of photons from the first nonlinear medium and producing through spontaneous parametric down conversion a second stream of quantum entangled signal and idler photon pairs;
an encoder receptive of the second stream of quantum entangled signal and idler photon pairs that places a quantum message on the signal and idler photon pairs to define a quantum signal at a signal wavelength and an idler wavelength;
a combiner receptive of the classical signal and the quantum signal that combines the classical and quantum signals into a propagated hybrid signal that occupies an optical spectrum that covers the first wavelength of the classical signal and the signal and idler wavelengths of the quantum signal, wherein the signal and idler wavelengths are centered around the first wavelength within the optical spectrum;
a receiver input receptive of the propagated hybrid signal;
a splitter coupled to the receiver input that splits the propagated signal on the basis of wavelength into a classical channel and a quantum channel;
a classical receiver coupled to the classical channel that demodulates the classical signal to extract a classical message;
a quantum receiver coupled to the quantum channel for extracting a quantum message from the quantum signal;
the quantum receiver having an optical parametric amplifier that boosts the intensity of the quantum signal by increasing the number of signal and idler photons to produce an amplified stream of signal and idler photons;
the optical parametric amplifier being supplied with optical energy to support optical parametric amplification from a second harmonic generation device receptive of the optical energy synchronized to the first wavelength;
and
a photodetector coupled to receive the amplified stream of signal and idler photons and to produce an electrical signal supplied to a demodulator that extracts a quantum message from the quantum signal.

14 more elements

A receiver for a hybrid quantum-classical communication system, comprising:

a receiver input receptive of a propagated signal that carries a classical signal at a first wavelength and concurrently conveys a quantum signal carried by signal and idler photon pairs having respective signal and idler wavelengths that are centered around the first wavelength within an optical spectrum;
a splitter coupled to the receiver input that splits the propagated signal on the basis of wavelength into a classical channel for the classical signal and a quantum channel for the quantum channel;
a classical receiver coupled to the classical channel that demodulates the classical signal to extract a classical message;
a quantum receiver coupled to the quantum channel for extracting a quantum message from the quantum signal;
the quantum receiver having an optical parametric amplifier that boosts the intensity of the quantum signal by increasing the number of signal and idler photons to produce an amplified stream of signal and idler photons;
the optical parametric amplifier being supplied with optical energy to support optical parametric amplification from a second harmonic generation device receptive of the optical energy synchronized to the first wavelength;
and
a photodetector coupled to receive the amplified stream of signal and idler photons and to produce an electrical signal supplied to a demodulator that extracts the quantum message from the quantum signal.

5 more elements

A method of hybrid quantum-classical communication comprising:

producing a light beam at a nominal wavelength with a transmit laser;
splitting the light beam into a first portion and a second portion;
modulating a classical message in the first portion of the light beam to produce a classical signal at the nominal wavelength;
passing the second portion of the light beam through a first nonlinear medium to producing a first stream of photons at a second wavelength that is shorter than the nominal wavelength;
passing the first stream of photons through a second nonlinear medium to produce a second stream of quantum entangled signal and idler photon pairs;
encoding a quantum message on the signal and idler photon pairs to define a quantum signal having signal photons at a signal wavelength and idler photons at an idler wavelength;
combining the classical signal and the quantum signal into a hybrid output signal that occupies an optical spectrum covering the nominal wavelength of the classical signal and the signal and idler wavelengths of the quantum signal, wherein the signal and idler wavelengths are centered around the nominal wavelength within the optical spectrum;
and
propagating the hybrid output signal through a communication channel.

6 more elements

Dependencies are inferred from the claim text.