Safe-mode OTDR method

Patent metadata

Field	Value
Publication number	US-9641243-B2
Application number	US-201615050146-A
Country	US
Kind code	B2
Filing date	Feb 22, 2016
Priority date	Feb 23, 2015
Publication date	May 2, 2017
Grant date	May 2, 2017

Abstract

A safe-mode OTDR method for characterizing an optical fiber link is provided, as well as an OTDR apparatus operating under such a safe mode. The method includes performing OTDR acquisitions along the fiber link using an OTDR apparatus connected at a proximal end of the optical fiber link, and operating under OTDR acquisition conditions that have been deemed safe for a communication device at a distal end of the fiber link. The obtained reflectometric trace, representing a proximal portion of the optical fiber link, is used to determine a partial-link loss value associated with the proximal portion of the fiber link. Modified acquisition conditions that are safe for the communication device are determined based on the partial-link loss value and on loss-related maximum rating parameters for the communication device. The process is repeated using the modified OTDR acquisition conditions until the end of the link has been reached.

First claim

The invention claimed is:

1. A safe-mode OTDR method for characterizing an optical fiber link having a proximal end and a distal end, a communication device being connected at the distal end of the optical fiber link, the method comprising the steps of:
a) obtaining initial OTDR acquisition conditions that are safe for the communication device;
b) performing an OTDR acquisition along the fiber link using an OTDR apparatus connected at the proximal end of the optical fiber link and operating under said OTDR acquisition conditions, thereby obtaining at least one reflectometric trace representing a proximal portion of the optical fiber link;
c) determining a partial-link loss value associated with the proximal portion of the optical fiber based on the OTDR acquisition performed at step b);
d) if the reflectometric trace extends to the distal end of the optical fiber link or to a break in said optical fiber link, determining modified OTDR acquisition conditions that are safe for the communication device based on the partial-link loss value determined at step c) and on maximum rating parameters for the communication device, and repeating steps b), c) and d) using said modified OTDR acquisition conditions.

2. The safe-mode OTDR method according to claim 1 , wherein the communication device is one of an optical transmitter or an optical receiver.

3. The safe-mode OTDR method according to claim 1 , wherein the OTDR acquisition conditions comprise a pulsewidth of OTDR test light pulses employed for the OTDR acquisition.

4. The safe-mode OTDR method according to claim 1 , wherein the initial OTDR acquisition conditions are based on an initially stipulated loss value in the optical fiber link.

5. The safe-mode OTDR method according to claim 4 , where the initially stipulated loss value in the optical fiber link is null.

6. The safe-mode OTDR method according to claim 1 , further comprising at step c) characterizing the proximal portion of the fiber link based on said at least one reflectometric trace.

7. The safe-mode OTDR method according to claim 6 , wherein said characterizing comprises determining at least one of a location, a loss or a reflectance parameter for one or more events along the proximal portion of the fiber link.

8. The safe-mode OTDR method according to claim 3 , wherein the maximum rating parameters comprise at least one of a maximum pulse energy value, a maximum average power value and a maximum peak pulse power value of the OTDR test light pulses.

9. The safe-mode OTDR method according to claim 3 , wherein the maximum rating parameters are based on a maximum rating model associated with the communication device.

10. The safe-mode OTDR method according to claim 3 , wherein the maximum rating parameters include a set of values for the OTDR acquisition conditions that have been empirically predetermined as safe for the communication device.

11. The safe-mode OTDR method according to claim 3 , wherein the maximum rating parameters are pre-recorded in the OTDR apparatus.

12. An OTDR apparatus for characterizing an optical fiber link having a proximal end and a distal end, a communication device being connected at the distal end of the optical fiber link, the OTDR apparatus comprising:
an acquisition module connectable at the proximal end of the optical fiber link and configured to perform a plurality of OTDR acquisitions along the fiber link;
a safe-mode module configured to:
a) obtain initial OTDR acquisition conditions that are safe for the communication device;
b) perform an OTDR acquisition along the fiber link using the acquisition module and operating under said OTDR acquisition conditions, thereby obtaining a reflectometric trace representing a proximal portion of the optical fiber link;
c) determine a partial-link loss value associated with the proximal portion of the optical fiber based on the OTDR acquisition performed at step b);
d) if the reflectometric trace extends to the distal end of the optical fiber link or indicates a fault in said optical fiber link, determine modified OTDR acquisition conditions that are safe for the communication device based on the partial-link loss value determined at step c) and on loss-related maximum rating parameters for the communication device, and repeat steps b), c) and d) using said modified OTDR acquisition conditions.

13. The OTDR apparatus according to claim 12 , wherein the acquisition module comprises a light generating assembly configured to generate at least one test light pulse to perform each of said OTDR acquisitions and wherein the OTDR acquisition conditions comprise a pulsewidth of the at least one test light pulse.

14. The OTDR apparatus according to claim 12 , wherein the safe-mode module is configured to obtain the initial OTDR acquisition conditions based on an initially stipulated loss value in the optical fiber link.

15. The OTDR apparatus according to claim 14 , where the initially stipulated loss value in the optical fiber link is null.

16. The OTDR apparatus according to claim 12 , further comprising an analyzing module configured to characterizing the proximal portion of the fiber link based on said at least one reflectometric trace.

17. The OTDR apparatus according to claim 13 , wherein the maximum rating parameters are based on a maximum rating model associated with the communication device.

18. The OTDR apparatus according to claim 13 , wherein the maximum rating parameters include a set of values for the OTDR acquisition conditions that have been empirically predetermined as safe for the communication device.

19. A non transitory computer readable storage medium with a computer program stored thereon, wherein the computer program is operable to perform a safe-mode OTDR method for characterizing an optical fiber link having a proximal end and a distal end, a communication device being connected at the distal end of the optical fiber link, and wherein the computer program instructs one or more processors to perform the steps of:
a) obtaining OTDR acquisition conditions that are safe for the communication device;
b) instructing an OTDR apparatus connected at the proximal end of the optical fiber link to perform an OTDR acquisition along the fiber link under said OTDR acquisition conditions, and obtaining from said OTDR apparatus a reflectometric trace representing a proximal portion of the optical fiber link;
c) determining a partial-link loss value associated with the proximal portion of the optical fiber based on the OTDR acquisition performed at step b);
d) determining if the reflectometric trace extends to the distal end of the optical fiber link or indicates a fault in said optical fiber link, and if not, determining modified acquisition conditions that are safe for the communication device based on the partial-link loss value determined at step c) and on loss-related maximum rating parameters for the communication device, and repeating steps b), c) and d) using said modified OTDR acquisition conditions.

20. The non transitory computer readable storage medium according to claim 19 , wherein the step of performing an OTDR acquisition comprises generating at least one test light pulse using the OTDR apparatus and wherein the OTDR acquisition conditions comprise a pulsewidth of the at least one test light pulse.

21. The non transitory computer readable storage medium according to claim 19 , further comprising at step c) characterizing the proximal portion of the fiber link based on said at least one reflectometric

Assignees

• Exfo Inc

Inventors

• Perron Stéphane

Classifications

• H04B10/071 Primary

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