Chip-scale transmitter for quantum cryptography

• US 20060222180A1
• Filed: 12/28/2005
• Published: 10/05/2006
• Est. Priority Date: 10/15/2002
• Status: Abandoned Application

• Current Assignee: Raytheon BBN Technologies Corp. (Rtx Corporation)
• Original Assignee: Raytheon BBN Technologies Corp. (Rtx Corporation)
• Inventors: Elliott, Brig Barnum
• Application Number:
  US11/318,636
• Publication Number:
  US 20060222180A1
• Time in Patent Office: Days
• US Class Current: 380/263
• CPC Class Codes: H04L 9/0852 Quantum cryptography transmission systems employing electromagnetic waves other than radio waves, e.g. light, infrared H04B10/00; wavelength-division multiplex systems H04J14/02; WDM arrangements H04J14/03

Abstract

A quantum cryptographic key distribution (QKD) transmitter includes an integrated photonic circuit configured to distribute encryption key material using quantum cryptographic mechanisms. The integrated photonic circuit further includes a first photon source, an interferometer coupled to the first photon source and a phase modulator coupled to the interferometer and configured to modulate a phase of photons emitted by the first photon source.

Claims

1. A quantum cryptographic key distribution (QKD) transmitter, comprising;

an integrated photonic circuit configured to distribute encryption key material using quantum cryptographic mechanisms.

2. The QKD transmitter of claim 1, wherein the integrated photonic circuit is implemented on a single chip.

3. The QKD transmitter of claim 1, further comprising:

control electronics coupled to the integrated photonic circuit and configured to control the operation of the integrated photonic circuit.

4. The QKD transmitter of claim 3, wherein the integrated photonic circuit and control electronics are implemented on a single chip.

5. The QKD transmitter of claim 3, wherein the integrated photonic circuit and the control electronics are implemented on different chips.

6. The QKD transmitter of claim 1, wherein the integrated photonic circuit comprises:

a first photon source;

an interferometer coupled to the first photon source; and

a phase modulator coupled to the interferometer and configured to modulate a phase of photons emitted by the first photon source.

7. The QKD transmitter of claim 6, wherein the first photon source comprises a pulsed light source.

8. The QKD transmitter of claim 6, wherein the first photon source comprises a continuous wave light source and further comprising:

a semiconductor optical amplifier (SOA) coupled to an output of the first photon source

9. The QKD transmitter of claim 6, wherein the integrated photonic circuit further comprises:

an attenuator coupled to an output of the interferometer.

10. The QKD transmitter of claim 9, wherein the integrated photonic circuit further comprises:

a second photon source; and

a combiner coupled to an output of the second photon source and to an output of the attenuator.

11. The QKD transmitter of claim 6, wherein the interferometer comprises a Mach-Zehnder interferometer.

12. The QKD transmitter of claim 1, wherein the integrated photonic circuit is implemented in III-V semiconducting materials.

13. The QKD transmitter of claim 1, wherein the integrated photonic circuit is implemented in silica or silicon material.

14. A system, comprising:

an interferometer formed in an integrated circuit;

a first laser formed in the integrated circuit and coupled to a first side of the interferometer;

an attenuator formed in the integrated circuit and coupled to a second side of the interferometer; and

a phase modulator formed in the integrated circuit and coupled to the interferometer.

15. The system of claim 14, wherein the interferometer, first laser, attenuator and phase modulator are integrated on a single chip.

16. The system of claim 14, further comprising:

a second laser formed in the integrated circuit; and

a combiner formed in the integrated circuit and coupled to the second laser and to an output of the attenuator.

17. The system of claim 16, further comprising:

an optical isolator coupled to an output of the combiner.

18. A quantum cryptographic key distribution (QKD) transmitter, comprising;

an integrated photonic circuit configured to distribute encryption key material using quantum cryptographic mechanisms via multiple channels.

19. The QKD transmitter of claim 18, wherein the integrated photonic circuit is configured to wavelength division multiplex the multiple channels.

20. The QKD transmitter of claim 18, wherein the integrated photonic circuit is configured to time division multiplex the multiple channels.

21. The QKD transmitter of claim 18, the integrated photonic circuit further comprising:

a first portion of the integrated photonic circuit configured to distribute encryption key material using quantum cryptographic mechanisms via a first channel of the multiple channels; and

a second portion of the integrated photonic circuit configured to distribute encryption key material using quantum cryptographic mechanisms via a second channel of the multiple channels.

22. The QKD transmitter of claim 21, wherein the first portion of the integrated photonic circuit comprises:

a first interferometer;

a first laser coupled to an input of the first interferometer and configured to transmit light over the first channel of the multiple channels;

a first phase modulator coupled to the first interferometer; and

a first attenuator coupled to an output of the first interferometer.

23. The QKD transmitter of claim 22, wherein the second portion of the integrated photonic circuit comprises:

a second interferometer;

a second laser coupled to an input of the second interferometer and configured to transmit light over the second channel of the multiple channels;

a second phase modulator coupled to the second interferometer; and

a second attenuator coupled to an output of the second interferometer.

24. The QKD transmitter of claim 23, wherein the integrated photonic circuit further comprises:

a combiner coupled to an output of the first and second attenuators; and

an optical isolator coupled to an output of the combiner.

25. A quantum cryptographic key distribution (QKD) transmitter, comprising;

an integrated photonic circuit configured to distribute encryption key material using at least one of dim light pulses or single photon light pulses and synchronization light pulses.

26. The QKD transmitter of claim 25, wherein the integrated photonic circuit uses 1 synchronization light pulse for N>

=1 dim or single photon light pulses.

27. The QKD transmitter of claim 25, wherein the at least one of dim light or single photon light pulses comprise light pulses at a first wavelength.

28. The QKD transmitter of claim 27, wherein the synchronization light pulses comprise light pulses at a second wavelength, wherein the first wavelength is different than the second wavelength.