Optical fiber polarization multiplexing

• US 10,097,307 B2
• Filed: 02/22/2017
• Issued: 10/09/2018
• Est. Priority Date: 02/22/2017
• Status: Active Grant

• Current Assignee: Meta Platforms, Inc. (f/k/a Facebook, Inc.)
• Original Assignee: Meta Platforms, Inc. (f/k/a Facebook, Inc.)
• Inventors: Lyubomirsky, Ilya
• Primary Examiner(s): Pascal, Leslie C
• Application Number:
  US15/439,877
• Publication Number:
  US 20180241498A1
• Time in Patent Office: 594 Days
• CPC Class Codes: H04B 10/0775 Performance monitoring and measurement of transmission parameters
• CPC Class Codes: H04B 10/614 comprising one or more polarization beam splitters, e.g. polarization multiplexed [PolMux] X-PSK coherent receivers, polarization diversity heterodyne coherent receivers H04J14/06 takes precedence
• CPC Class Codes: H04B 2210/078 using a separate wavelength
• CPC Class Codes: H04J 14/02 Wavelength-division multiplex systems
• CPC Class Codes: H04J 14/0307 Multiplexers; Demultiplexers
• CPC Class Codes: H04J 14/06 Polarisation multiplex systems

Abstract

Optical fiber data communications are described. A comb laser can provide light at a first wavelength and a second wavelength. Using that light, polarization multiplexing circuitry can generate an optical signal having different polarization components and transceivers can transmit the optical signal having the first wavelength and a probe having the second wavelength via an optical fiber. A polarimeter can determine characteristics of the polarization of the probe. Based on the characteristics, a polarization controller can adjust a polarization of the optical signal. The optical signal can then be split into different polarization components.

Claims

1. An optical fiber data communications system, comprising:

a comb laser configured to provide light at a first wavelength and a second wavelength, the first wavelength and the second wavelength having different wavelengths;

polarization multiplexing circuitry configured to receive light at the first wavelength and generate an optical signal having a first polarization component and a second polarization component, the first polarization component and the second polarization component corresponding to different polarizations, wherein the optical fiber data communications system is configured to transmit via an optical fiber the optical signal at the first wavelength and a probe corresponding to the light at the second wavelength;

a wavelength de-multiplexer configured to separate the probe corresponding to the light at the second wavelength from the optical signal at the first wavelength;

a polarimeter configured to receive the probe separated by the wavelength de-multiplexer and determine characteristics of a polarization of the probe;

a polarization controller configured to receive the optical signal transmitted via the optical fiber and adjust a polarization of the optical signal based on the characteristics of the polarization of the probe; and

polarization de-multiplexing circuitry configured to split the received optical signal with the adjusted polarization into the first polarization component utilized to detect first communicated data and the second polarization component utilized to detect second communicated data.

2. The system of claim 1, wherein the characteristics of the polarization of the probe include a state of polarization of the probe.

3. The system of claim 1, wherein the characteristics of the polarization of the probe represent a difference between the polarization of the probe received from the optical fiber and an expected polarization of the probe.

4. The system of claim 1, wherein the characteristics of the polarization of the probe is based on a comparison of the polarization of the probe received from the optical fiber and an expected polarization of the probe.

5. The system of claim 1, wherein adjusting the polarization of the optical signal includes aligning the polarization of the optical signal with an expected polarization axis of a polarization beam splitter of the polarization de-multiplexing circuitry.

6. The system of claim 1, wherein the probe is unmodulated, and the probe is polarized corresponding to the polarization of the first polarization component of the optical signal.

7. The system of claim 1, wherein the polarization controller adjusts the polarization of the optical signal to account for birefringence effects of the optical fiber on the polarization of the probe.

8. A system, including:

a polarization circuit configured to receive a probe corresponding to light having a first wavelength from an optical fiber, and configured to receive an optical signal corresponding to light having a second wavelength from the optical fiber, the first wavelength and the second wavelength having different wavelengths, and the probe corresponding to the light having the first wavelength has been separated from the optical signal corresponding to the light having the second wavelength, and configured to adjust a polarization of the optical signal based on characteristics of a polarization of the probe separated from the optical signal; and

a polarization beam splitter configured to split the received optical signal with the adjusted polarization into a first polarization component utilized to detect first communicated data and a second polarization component utilized to detect second communicated data, wherein the first polarization component and the second polarization component correspond to different polarizations.

9. The system of claim 8, wherein the polarization circuit is configured to adjust the polarization of the optical signal including by being configured to align the polarization of the optical signal with an expected polarization axis of the polarization beam splitter.

10. The system of claim 8, wherein the characteristics of the polarization of the probe include a state of the polarization of the probe.

11. The system of claim 8, wherein the characteristics of the polarization of the probe represent a difference between the polarization of the probe separated from the optical signal and an expected polarization of the probe.

12. The system of claim 11, wherein the polarization of the optical signal is adjusted based on the difference.

13. The system of claim 8, wherein the characteristics of the probe include an effect of birefringence of the optical fiber on the probe.

14. The system of claim 8, wherein the characteristics of the polarization of the probe is based on a comparison of an expected polarization of the probe and the polarization of the probe received from the optical fiber.

15. The system of claim 14, wherein the comparison represents birefringence effects of the optical fiber on the polarization of the optical signal.

16. The system of claim 15, wherein the probe is unmodulated.

17. A method, comprising:

receiving an optical signal corresponding to light having a first wavelength from an optical fiber;

receiving a probe corresponding to light having a second wavelength from the optical fiber, the first wavelength and the second wavelength having different wavelengths, including by separating from the optical signal having the first wavelength, the probe corresponding to the light having the second wavelength;

determining characteristics of polarization of the received probe; and

adjusting a polarization of the optical signal based on the characteristics of the polarization of the received probe separated from the optical signal having the first wavelength;

separating the received optical signal with the adjusted polarization into a first polarization component utilized to detect first communicated data and a second polarization component utilized to detect second communicated data, the first polarization component and the second polarization component having different polarizations.

18. The method of claim 17, wherein the probe is unmodulated.

19. The method of claim 17, wherein determining characteristics of the polarization of the received probe includes determining a state of polarization of the received probe.

20. The method of claim 17, wherein the characteristics of the polarization of the received probe represent a comparison between the polarization of the received probe received from the optical fiber and an expected polarization of the received probe.