Architecture for reconfigurable quantum key distribution networks based on entangled photons directed by a wavelength selective switch

1. A method comprising:

generating entangled photon pairs with known frequency relationships, wherein each of the entangled photon pairs is centered at an optical source frequency;

concurrently distributing the entangled photon pairs among pairs of a plurality of users communicating over an optical network via a reconfigurable wavelength routing device based on shared optical source frequencies among the entangled photon pairs and scheduled connection and duration times; and

establishing a key exchange between the plurality of users.

2. The method recited in claim 1 , in which distributing the entangled photon pairs among the plurality of users is accomplished via ports of a wavelength selective switch.

3. The method recited in claim 1 , further comprising segregating a broadband stream of entangled photon pairs into individual wavebands at a plurality of ports serving each of the plurality of users respectively.

4. The method recited in claim 3 , further comprising concurrently communicating with a waveband at each of the plurality of ports.

5. The method recited in claim 1 , further comprising concurrently establishing a plurality of key exchange connections between a selected pair of the plurality of users.

6. The method recited in claim 1 , further comprising reconfiguring the wavelength routing device to establish a new key exchange connection among the plurality of users.

7. The method recited in claim 1 , further comprising reconfiguring the wavelength routing device to terminate a key exchange connection among the plurality of users.

8. The method recited in claim 1 , in which generating entangled photon pairs is accomplished by parametric down-conversion.

9. The method recited in claim 1 , in which generating entangled photon pairs is accomplished by degenerate four-wave mixing.

10. A system comprising:

an optical source adapted to generate entangled photon pairs with known frequency relationships, wherein each of the entangled photon pairs is centered at a source frequency; and

a reconfigurable wavelength routing device adapted to communicate with the optical source to:

concurrently distribute the entangled photon pairs among pairs of a plurality of users communicating over an optical network based on shared source frequencies among the entangled photon pairs and scheduled connection and duration times; and

establish a key exchange between the plurality of users.

11. The system recited in claim 10 , wherein the optical source is adapted to produce entangled photon pairs whose frequencies obey a known mathematical relation.

12. The system recited in claim 10 , wherein the reconfigurable wavelength routing device is adapted to selectively distribute the entangled photon pairs among a plurality of output ports according to a frequency of the entangled photon pairs.

13. The system recited in claim 12 , wherein the reconfigurable wavelength routing device is adapted to selectively distribute entangled photon pairs at a plurality of distinct frequencies to a single output port.

14. The system recited in claim 12 , wherein the reconfigurable wavelength routing device is adapted to selectively multicast entangled photon pairs at a given frequency to a plurality of output ports.

15. The system recited in claim 12 , wherein the reconfigurable wavelength routing device comprises a wavelength selective switch, adapted to selectively communicate signals between ports of the wavelength selective switch to the plurality of users individually.

16. The system recited in claim 10 , wherein the reconfigurable wavelength routing device is adapted to establish a plurality of concurrent key exchanges between users among the plurality of users.

17. A memory containing machine readable instructions which, when executed by a processor, enable a device to secure communications between a plurality of users communicating over an optical network by:

generating entangled photon pairs with known frequency relationships, wherein each of the entangled photon pairs is centered at an optical source frequency;

concurrently distributing the entangled photon pairs among pairs of a plurality of users communicating over an optical network via a reconfigurable wavelength routing device based on shared optical source frequencies among the entangled photon pairs and scheduled connection and duration times; and

establishing a key exchange between the plurality of users.

18. The memory recited in claim 17 , wherein the reconfigurable wavelength routing device is a wavelength selective switch.

19. The memory recited in claim 17 , wherein the reconfigurable wavelength routing device is reconfigured according to the machine-readable instructions to establish a new key exchange connection among the plurality of users.