Optical fiber recognition using backscattering pattern

Patent metadata

Field	Value
Publication number	US-11650128-B2
Application number	US-202117360357-A
Country	US
Kind code	B2
Filing date	Jun 28, 2021
Priority date	Jun 30, 2020
Publication date	May 16, 2023
Grant date	May 16, 2023

Abstract

There are provided methods and systems that enable the use of the backscattering pattern produced by an optical fiber in an OTDR trace as a signature (also referred to herein as the “RBS fingerprint”) to recognize an optical fiber. It was found that it may be difficult to obtain repeatable signatures as those are sensitive to the wavelength of the OTDR laser source and the temperature of the fiber. OTDR methods and systems that are adapted to compare the backscattering pattern in a more repeatable manner are therefore provided. Once the repeatability issue is overcome, such signature can be used for identification purposes and enable new applications.

First claim

The invention claimed is:

1. A method for comparing Optical Time-Domain Reflectometric (OTDR) signatures for optical fiber recognition, the method comprising:
receiving a set of backscattering patterns obtained over a first span of a first optical fiber link for different values of optical fiber temperatures or different values of OTDR laser center wavelengths, wherein each backscattering pattern corresponds to at least a portion of an OTDR trace acquired over the first span of the first optical fiber link;
receiving a backscattering pattern obtained over a second span of a second optical fiber link and corresponding to at least a portion of an OTDR trace acquired over the second span of the second optical fiber link; and
comparing the backscattering pattern of said second span to the set of backscattering patterns of said first span to determine if the backscattering pattern of said second span matches one of the backscattering patterns of said set;
wherein said second span is determined to be the same as said first span if a match is found.

2. The method as claimed in claim 1 , wherein said set of backscattering patterns is previously obtained over the first span for different values of optical fiber temperatures and wherein said second span of optical fiber is part of an optical fiber to be recognized.

3. The method as claimed in claim 1 , wherein said set of backscattering patterns is previously obtained over the first span for different values of OTDR laser center wavelengths and wherein said second span of optical fiber is part of an optical fiber to be recognized.

4. The method as claimed in claim 1 , wherein said backscattering pattern is previously obtained over the second span, wherein said first span of optical fiber is part of an optical fiber to be recognized and wherein said set of backscattering patterns is obtained for different values of OTDR laser center wavelengths.

5. The method as claimed in claim 1 , wherein the step of comparing comprises: calculating a correlation coefficient of at least one of said backscattering patterns of said first span and said backscattering pattern of said second span and comparing the correlation coefficient to a threshold to determine if said second span is the same as said first span.

6. The method as claimed in claim 1 , wherein the first and the second span of optical fiber each correspond to sub-portions of optical fiber links over which an OTDR trace was acquired.

7. The method as claimed in claim 1 , wherein said backscattering patterns are acquired while the OTDR laser source is being polarization scrambled.

8. An OTDR system for comparing Optical Time-Domain Reflectometric (OTDR) signatures for optical fiber recognition, the OTDR system comprising:
an OTDR acquisition device connectable toward an end of the second optical fiber link for performing one or more OTDR acquisitions toward the second optical fiber link, wherein each OTDR acquisition is performed by propagating a test signal in the optical fiber link under test and detecting corresponding return light from the second optical fiber link so as to obtain an OTDR trace representing backscattered and reflected light as a function of distance in the optical fiber link; and
a data storage storing a prerecorded set of backscattering patterns obtained over a first span of a first optical fiber link for different values of optical fiber temperatures or different values of OTDR laser center wavelengths, wherein each backscattering pattern corresponds to at least a portion of an OTDR trace acquired over the first span of first optical fiber link;
a processing unit comprising:
a signature recognition module comprising a comparison engine configured for comparing the backscattering pattern obtained over a second span of the second optical fiber link and corresponding to at least a portion of said OTDR trace, to the set of backscattering patterns of said first span to determine if the backscattering pattern of said second span matches one of the backscattering patterns of said set, wherein said second span is determined to be the same as said first span if a match is found.

9. The OTDR system as claimed in claim 8 , wherein said set of backscattering patterns stored in said data storage is previously obtained over the first span for different values of optical fiber temperatures.

10. The OTDR system as claimed in claim 8 , wherein said set of backscattering patterns stored in said data storage is previously obtained over the first span for different values of OTDR laser center wavelengths.

11. The OTDR system as claimed in claim 8 , wherein said comparison engine is configured for calculating a correlation coefficient of at least one of said backscattering patterns of said first span and said backscattering pattern of said second span and comparing the correlation coefficient to a threshold to determine if said second span is the same as said first span.

12. The OTDR system as claimed in claim 8 , wherein the first and the second span of optical fiber each correspond to sub-portions of optical fiber links over which an OTDR trace was acquired.

13. The OTDR system as claimed in claim 8 , wherein said OTDR acquisition device comprises a polarization scrambler to scramble said test signal.

14. An OTDR system for comparing Optical Time-Domain Reflectometric (OTDR) signatures for optical fiber recognition, the OTDR system comprising:
a tunable OTDR acquisition device connectable toward an end of a first optical fiber link for performing one or more OTDR acquisitions toward the first optical fiber link, wherein each OTDR acquisition is performed by propagating a test signal in the optical fiber link under test and detecting corresponding return light from the first optical fiber link so as to obtain an OTDR trace representing backscattered and reflected light as a function of distance in the optical fiber link; and
a data storage storing at least one pre-recorded backscattering pattern obtained over a second span of a second optical fiber link, wherein the backscattering pattern corresponds to at least a portion of an OTDR trace acquired over the second span of the second optical fiber link; and
a processing unit configured for:
comparing backscattering pattern obtained over a first span of said first optical fiber link and corresponding to at least a portion of OTDR trace, to said pre-recorded backscattering pattern of said second span to determine if the backscattering pattern of said first span matches the backscattering patterns of said second span, wherein said second span is determined to be the same as said first span if a match is found; and
if no match is found, tuning an OTDR laser source of said OTDR acquisition device to a different value of laser center wavelength to perform another OTDR acquisition and repeating the comparing step to find a match.

15. The OTDR system as claimed in claim 14 , wherein said processing unit is further configured for calculating a correlation coefficient of at least one of said backscattering patterns of said first span and said backscattering pattern of said second span and comparing the correlation coefficient to a threshold to determine if said second span is the same as said first span.

16. The OTDR system as claimed in claim 14 , wherein the first and the second span of optical fiber each correspond to sub-portions of optical fiber links over which an OTDR trace was acquired.

17. The OTDR system as claimed in claim 14 , wherein said OTDR acquisition device comprises a polarization scrambler to scramble said test signal.

Assignees

• Exfo Inc

Inventors

• Leclerc Michel
• Gosselin-Badaroudine Pascal
• Perron Stephane

Classifications

• G01M11/3127 Primary

  using multiple or wavelength variable input source · CPC title

• H04B10/071

  using a reflected signal, e.g. using optical time domain reflectometers [OTDR] · CPC title

• G01M11/3109

  Reflectometers detecting the back-scattered light in the time-domain, e.g. OTDR · CPC title

• G01M11/3145 Primary

  Details of the optoelectronics or data analysis · CPC title

• G06F2218/16

  by matching signal segments · CPC title