Photonic quantum memory with polarization-to-time entanglement conversion and time-to-polarization entanglement conversion

Patent metadata

Field	Value
Publication number	US-10222822-B2
Application number	US-201715852039-A
Country	US
Kind code	B2
Filing date	Dec 22, 2017
Priority date	May 10, 2012
Publication date	Mar 5, 2019
Grant date	Mar 5, 2019

Abstract

A photonic quantum memory is provided. The photonic quantum memory includes entanglement basis conversion module configured to receive a first polarization-entangled photon pair and to produce a second entangled photon pair. The second polarization-entangled photon pair can be a time-bin entangled or a propagation direction-entangled photon pair. The photonic quantum memory further includes a photonic storage configured to receive the second entangled photon pair from the basis conversion module and to store the second entangled photon pair.

First claim

What is claimed is:

1. A memory device, comprising:
a polarization-to-time-bin entanglement conversion (P2T) module configured to receive a polarization-entangled photon pair and to generate a time-bin entangled photon pair; and
a storage module configured to store the time-bin entangled photon pair, wherein the storage module comprises an entrance fiber optic path coupled to a first controllable mirror, an exit fiber optic path coupled to a second controllable mirror, and a storage fiber optic path coupling the first and second controllable mirrors.

2. The memory device of claim 1 , further comprising a time-bin-to-polarization entanglement conversion (T2P) module configured to receive the time-bin entangled photon pair and to re-generate the polarization-entangled photon pair based on the time-bin entangled photon pair.

3. The memory device of claim 2 , further comprising a polarizing beam splitter configured to:
receive a photon of the time-bin entangled photon pair from the P2T module and to direct the photon to the entrance fiber optic path; and
receive the photon from the exit fiber optic path and to direct the photon to the T2P module.

4. The memory device of claim 1 , wherein the entrance fiber optic path is configured to change a photon of the time-bin entangled photon pair from a horizontal orientation to a vertical orientation by a quarter twist.

5. The memory device of claim 1 , wherein the first controllable mirror comprises a coupler with first, second, third, and fourth ports and a fiber optic loop, and wherein:
the first port is coupled to the entrance fiber optic path;
the second port is coupled to a first end of the fiber optic loop;
the third port is coupled to a second end of the fiber optic loop; and
the fourth port is coupled to the storage fiber optic path.

6. The memory device of claim 5 , wherein the fiber optic loop comprises:
a phase shifter; and
a control module configured to adjust an index of refraction associated with the phase shifter.

7. The memory device of claim 1 , wherein the second controllable mirror comprises a coupler with first, second, third, and fourth ports and a fiber optic loop, and wherein:
the first port is coupled to the exit fiber optic path;
the second port is coupled to a first end of the fiber optic loop;
the third port is coupled to a second end of the fiber optic loop; and
the fourth port is coupled to the storage fiber optic path.

8. The memory device of claim 1 , wherein the storage fiber optic path comprises a polarization-maintaining fiber.

9. A method, comprising:
receiving a polarization-entangled photon pair;
generating a time-bin entangled photon pair based on the polarization-entangled photon pair; and
storing, in a storage module, the time-bin entangled photon pair, wherein the storage module comprises an entrance fiber optic path coupled to a first controllable mirror, an exit fiber optic path coupled to a second controllable mirror, and a storage fiber optic path coupling the first and second controllable mirrors.

10. The method of claim 9 , further comprising:
receiving the time-bin entangled photon pair; and
re-generating the polarization-entangled photon pair based on the time-bin entangled photon pair.

11. The method of claim 9 , wherein storing the time-bin entangled photon pair comprises changing a photon of the time-bin entangled photon pair from a horizontal orientation to a vertical orientation by a quarter twist.

12. The method of claim 9 , wherein storing the time-bin entangled photon pair comprises maintaining a polarization of the time-bin entangled photon pair.

13. A system, comprising:
a memory device configured to store photons, the memory device comprising:
a polarization-to-time-bin entanglement conversion (P2T) module configured to receive a polarization-entangled photon pair and to generate a time-bin entangled photon pair;
a storage module configured to store the time-bin entangled photon pair, wherein the storage module comprises an entrance fiber optic path coupled to a first controllable mirror, an exit fiber optic path coupled to a second controllable mirror, and a storage fiber optic path coupling the first and second controllable mirrors; and
a time-bin-to-polarization entanglement conversion (T2P) module configured to receive the time-bin entangled photon pair and to re-generate the polarization-entangled photon pair based on the time-bin entangled photon pair; and

a computing unit configured to access the re-generated polarization-entangled photon pair from the memory device.

14. The system of claim 13 , further comprising:
a circulator module configured to direct the photons from a first port to a second port coupled to the P2T conversion module and to direct the re-generated polarization-entangled photon pair from the T2P module to the computing unit.

15. The system of claim 14 , further comprising:
a half wave plate positioned between the circulator module and the computing unit to adjust a polarization shift in the re-generated polarization-entangled photon pair.

16. The system f claim 13 , wherein the memory device further comprises a polarizing beam splitter configured to:
receive a photon of the time-bin entangled photon pair from the P2T module and to direct the photon to the entrance fiber optic path; and
receive the photon from the exit fiber optic path and to direct the photon to the T2P module.

17. The system of claim 13 , wherein the entrance fiber optic path is configured to change a photon of the time-bin entangled photon pair from a horizontal orientation to a vertical orientation by a quarter twist.

18. The system of claim 13 , wherein the first controllable mirror comprises a coupler with first, second, third, and fourth ports and a fiber optic loop, and wherein:
the first port is coupled to the entrance fiber optic path;
the second port is coupled to a first end of the fiber optic loop;
the third port is coupled to a second end of the fiber optic loop; and
the fourth port is coupled to the storage fiber optic path.

19. The system of claim 18 , wherein the fiber optic loop comprises:
a phase shifter; and
a control module configured to adjust an index of refraction associated with the phase shifter.

20. The system of claim 13 , wherein the storage fiber optic path comprises a polarization-maintaining fiber.

Assignees

• Mitre Corp

Inventors

• Gilbert Gerald N
• Hodges Jonathan S
• Pappas Stephen Peter
• Weinstein Yaakov Shmuel

Classifications

• G02F1/3551

  Crystals · CPC title

• G11C13/04

  using optical elements {; using other beam accessed elements, e.g. electron or ion beam} · CPC title

• G06E1/00 Primary

  Devices for processing exclusively digital data · CPC title

• G11C13/048

  using other optical storage elements · CPC title

• G02F1/0136

  for the control of polarisation, e.g. state of polarisation [SOP] control, polarisation scrambling, TE-TM mode conversion or separation (G02F1/0353 takes precedence) · CPC title