Fiber-based communication

Patent metadata

Field	Value
Publication number	US-10063323-B2
Application number	US-201415316869-A
Country	US
Kind code	B2
Filing date	Jun 9, 2014
Priority date	Jun 9, 2014
Publication date	Aug 28, 2018
Grant date	Aug 28, 2018

Abstract

In accordance with an example embodiment of the present invention, there is provided an apparatus comprising a dual-rail encoder (120) configured to receive light from a light source and to output dual-rail encoded light, a combiner (130) configured to convert the dual-rail encoded light into polarization encoded light, and at least one processing core configured to obtain compensation adjustment information concerning a fiber (145) and to control the dual-rail encoder (120) based at least in part on the compensation adjustment information.

First claim

The invention claimed is:

1. An apparatus comprising:
a dual-rail encoder configured to receive light from a light source and to output dual-rail encoded light, the dual-rail encoder configured to at least pre-compensate, based on feedback information from a receiver detecting polarization rotation via qubits of at least two different bases in received dual-rail encoded light;
a combiner, coupled to the dual-rail encoder, configured to at least convert the pre-compensated dual-rail encoded light into polarization encoded light for transmission; and
a controller configured to obtain at least the feedback information including compensation adjustment information and to at least control, based at least in part on the compensation adjustment information, the dual-rail encoder to pre-compensate for the polarization rotation.

2. The apparatus of claim 1 , wherein the controller is configured to at least obtain the compensation adjustment information by at least causing the apparatus to transmit first polarization-encoded light via a fiber, to receive the feedback concerning reception of the transmitted first polarization-encoded light, and to at least compare the feedback to information concerning the first polarization-encoded light.

3. The apparatus of claim 1 , wherein the dual-rail encoder is configured to at least modify at least one of amplitude and phase properties of the light received from the light source.

4. The apparatus of claim 1 , wherein the dual-rail encoder comprises at least one phase shifter.

5. The apparatus of claim 1 , wherein the at least one phase shifter is configurable by applying at least one of a voltage and an optical signal.

6. The apparatus of claim 1 , wherein the dual-rail encoder comprises at least one coupler.

7. The apparatus of claim 1 , wherein the combiner comprises a fiber-based polarization beam splitter.

8. The apparatus of claim 1 , wherein the apparatus further comprises an attenuator configured to reduce an intensity of at least one of the dual-rail encoded light, polarization encoded light, and the light from the light source to a single-photon regime.

9. An apparatus comprising:
a polarization rotator configured to at least convert received polarization-encoded and dual-rail encoded light to the dual-rail encoded light; and
at least one decoder configured to measure polarization rotation in the dual-rail encoded light via qubits of at least two different bases, the polarization rotation incurred during transmission of the received light to the apparatus.

10. The apparatus according to claim 9 , wherein the at least one decoder comprises at least one single photon detector or one photo-detector.

11. The apparatus according to claim 9 , further comprising at least one processing core is configured to at least obtain the compensation adjustment information by comparing a first output of the at least one decoder to first information received from a second apparatus, the first information characterizing a transmission of light that the at least one decoder measured to produce the first output.

12. The apparatus according to claim 11 , wherein the compensation adjustment information corrects a distortion caused by birefringence of a fiber.

13. A method, comprising:
encoding, based on compensation information, light received from a light source to produce dual-rail encoded light;
converting the dual-rail encoded light into polarization encoded light;
obtaining the compensation adjustment information, the compensation information including feedback information from a receiver detecting polarization rotation via qubits of at least two different bases in received dual-rail encoded light; and
controlling the encoding based at least in part on the compensation adjustment information.

14. The method of claim 13 , wherein obtaining the compensation adjustment information comprises transmission of first polarization-encoded light a fiber, receiving feedback concerning reception of the transmitted first polarization-encoded light and comparing the feedback to information concerning the first polarization-encoded light.

15. The method of claim 13 , wherein the encoding comprises modifying at least one of amplitude and phase properties of the light received from the light source.

16. The method of claim 13 , wherein the encoding comprises using at least one phase shifter.

17. The method of claim 16 , wherein using the at least one phase shifter comprises applying at least one of a voltage and an optical signal to the at least one phase shifter.

18. The method of claim 13 , wherein the converting comprises using a fiber-based polarization beam splitter.

19. The method of claim 13 , further comprising reducing an intensity of at least one of the dual-rail encoded light, polarization encoded light, and the light from the light source to a single-photon regime.

20. A method comprising:
measuring polarization rotation in dual-rail encoded light via qubits of at least two different bases;
obtaining, based on the measured polarization rotation, compensation adjustment information; and
causing adjusting of at least one of the dual-rail encoded light and an output of at least one detector based at least in part on the compensation adjustment information.

21. The method according to claim 20 , wherein the measuring comprises using at least one detector, the at least one detector comprising at least one single photon detector or one photo-detector.

22. The method according to claim 20 , wherein the compensation adjustment information is obtained by comparing a first output of the measuring to first information received from a second apparatus, the first information characterizing a transmission of light that is measured to produce the first output.

23. The method according to claim 20 , wherein the compensation adjustment information corrects a distortion caused by birefringence of a fiber.

24. A non-transitory computer readable medium having stored thereon a set of computer readable instructions that, when executed by at least one processor, cause an apparatus to at least:
encode, based on compensation information, light received from a light source to output dual-rail encoded light;
convert the dual-rail encoded light into polarization encoded light;
obtain the compensation adjustment information, the compensation information including feedback information from a receiver detecting polarization rotation via qubits of at least two different bases in received dual-rail encoded light; and
control the encoding based at least in part on the compensation adjustment information.

25. A non-transitory computer readable medium having stored thereon a set of computer readable instructions that, when executed by at least one processor, cause an apparatus to at least:
measure polarization rotation in dual-rail encoded light via qubits of at least two different bases;
obtain, based on the measured polarization rotation, compensation adjustment information; and
cause adjusting of at least one of the dual-rail encoded light and an output of at least one detector based at least in part on the compensation adjustment information.

Assignees

• Nokia Technologies Oy

Inventors

• Bitauld David
• Wabnig Joachim
• Niskanen Antti
• Li Hongwei

Classifications

• H04B10/85 Primary

  Protection from unauthorised access, e.g. eavesdrop protection · CPC title

• H04B10/541

  Digital intensity or amplitude modulation · CPC title

• H04B10/70 Primary

  Photonic quantum communication · CPC title

• H04J14/06

  Polarisation multiplex systems · CPC title

• H04B10/2572

  due to forms of polarisation-dependent distortion other than PMD · CPC title