Test device with both OTDR and WDM power meter modes

Patent metadata

Field	Value
Publication number	US-11035753-B2
Application number	US-202016815105-A
Country	US
Kind code	B2
Filing date	Mar 11, 2020
Priority date	Mar 12, 2019
Publication date	Jun 15, 2021
Grant date	Jun 15, 2021

Abstract

There is provided a test device and a test method that combine both tunable OTDR and WDM power meter functionalities into the same integrated optoelectronic test hardware, such that the tunable OTDR and the WDM power meter functions share optoelectronic components, thereby reducing the hardware cost and the overall form factor and weight of the test device. With the proposed configuration, both tunable OTDR and WDM power meter functionalities may be provided via a single test port to be connected to the optical fiber link under test. By connecting the fiber to a single test port, the number of manipulations to be performed by technicians is reduced and two tests can be performed in a single connection operation out of the same test port.

First claim

The invention claimed is:

1. A test device comprising:
a test port connectable toward an optical fiber link;
a pulsed tunable laser source configured for generating and launching toward the optical fiber link and via said test port, a pulsed test signal within a selected wavelength-division multiplexed (WDM) channel;
a tunable optical filter receiving light from the optical fiber link via said test port and configured to filter out optical power outside of the selected WDM channel before detection;
a detection circuit connected to the tunable filter and configured to detect light from the optical fiber link within the selected WDM channel;
an OTDR module configured to, in an OTDR mode, set an emission wavelength of the pulsed tunable laser source for generating a pulsed test signal in the selected WDM channel, set a center wavelength of the tunable filter within the selected WDM channel and acquire from the detection circuit, an OTDR trace representing backscattered and reflected light as a function of distance in the optical fiber link; and
a WDM power meter module configured to, in a WDM power meter mode, set the center wavelength of the tunable filter within the selected WDM channel and acquire from the detection circuit, an optical power value representing an optical power level of light from the optical fiber link within the selected WDM channel.

2. The test device as claimed in claim 1 , wherein the detection circuit comprises an avalanche photodiode and an analog-to-digital converter.

3. The test device as claimed in claim 1 , wherein the OTDR module further comprises:
an OTDR analyzing module configured for identifying one or more events along the optical fiber link from at least one of said OTDR trace, and for estimating a value of at least one characteristic associated with each said one or more events.

4. The test device as claimed in claim 1 , wherein the WDM power meter module is further configured to repeat the optical power value acquisitions for a plurality of WDM channels.

5. The test device as claimed in claim 4 , wherein the WDM power meter module further comprises:
a WDM power meter analyzing module configured for recording acquired optical power values associated with the plurality of WDM channels.

6. The test device as claimed in claim 1 , wherein the detection circuit comprises a first photodetector used, in the OTDR mode, to detect a return light signal corresponding to the pulsed test signal as received from the optical fiber link via said test port and filtered by said tunable filter, so as to obtain the OTDR trace representing backscattered and reflected light as a function of distance in the optical fiber link.

7. The test device as claimed in claim 6 , wherein said first photodetector is further used, in a WDM power meter mode, to detect an optical power level of light from the optical fiber link within the selected WDM channel.

8. The test device as claimed in claim 6 , wherein the detection circuit comprises a second photodetector used, in a WDM power meter mode, to detect an optical power level of light from the optical fiber link within the selected WDM channel.

9. The test device as claimed in claim 6 , wherein the first photodetector comprises an avalanche photodiode.

10. The test device as claimed in claim 8 , wherein the first photodetector comprises an avalanche photodiode and the second photodetector comprises a p-n junction photodiode.

11. The test device as claimed in claim 10 , wherein the second photodetector comprises a PIN photodiode.

12. A test method for testing an optical fiber link using a test device having a WDM power meter module and an OTDR module, the test method comprising:
in an OTDR mode:
setting an emission wavelength of a pulsed tunable laser source for generating a pulsed test signal in a selected wavelength-division multiplexed (WDM) channel;
using the pulsed tunable laser source to generate and launch toward the optical fiber link, a pulsed test signal within a selected WDM channel, via a test port connectable toward the optical fiber link;
setting a center wavelength of a tunable filter within the selected WDM channel;
using the tunable optical filter receiving light from the optical fiber link via said test port, to filter out optical power outside of the selected WDM channel before detection; and
using a detection circuit connected to the tunable filter to acquire an OTDR trace representing backscattered and reflected light as a function of distance in the optical fiber link; and

in a WDM power meter mode:
setting the center wavelength of the tunable filter within the selected WDM channel;
using the tunable optical filter receiving light from the optical fiber link via said test port, to filter out optical power outside of the selected WDM channel before detection; and
in absence of the pulsed test signal, using a detection circuit connected to the tunable filter to acquire an optical power value representing an optical power level of light from the optical fiber link within the selected WDM channel.

13. The test method as claimed in claim 12 , further comprising:
in the OTDR mode:
identifying one or more events along the optical fiber link from at least one of said OTDR trace, and
estimating a value of at least one characteristic associated with each said one or more events.

14. The test method as claimed in claim 12 , further comprising:
in the WDM power meter mode:
repeating the optical power value acquisitions for a plurality of WDM channels; and
recording acquired optical power values associated with the plurality of WDM channels.

15. The test method as claimed in claim 12 , further comprising:
in the OTDR mode: detecting return light signal corresponding to the pulsed test signal as received from the optical fiber link via said test port and filtered by said tunable filter using a first photodetector and a first analog-to-digital converter, so as to obtain the OTDR trace representing backscattered and reflected light as a function of distance in the optical fiber link.

16. The test device as claimed in claim 15 , further comprising:
in the WDM power meter mode: detecting an optical power level of light from the optical fiber link within the selected WDM channel using a second photodetector and a second analog-to-digital converter.

17. The test method as claimed in claim 12 , further comprising:
in the OTDR mode: detecting return light signal corresponding to the pulsed test signal as received from the optical fiber link via said test port and filtered by said tunable filter using an avalanche photodetector and a first analog-to-digital converter, so as to obtain the OTDR trace representing backscattered and reflected light as a function of distance in the optical fiber link.

18. The test device as claimed in claim 15 , further comprising:
in the WDM power meter mode: detecting an optical power level of light from the optical fiber link within the selected WDM channel using a p-n junction photodetector and a second analog-to-digital converter.

19. A test method for testing an optical fiber link using a test device having a WDM power meter module and an OTDR module, the method comprising:
using the WDM power meter module:
for each of a set of WDM channels, measuring an optical power value representing an optical power level of light from the optical fiber link within the corresponding WDM channel;

comparing measured optical power values to a power level threshold;
based upon a determination that the optical power value me

Assignees

• Gagnon Jimmy
• Leclerc Michel
• Perron Stephane
• Exfo Inc

Inventors

• Gagnon Jimmy
• Leclerc Michel
• Perron Stephane

Classifications

• G01M11/3145 Primary

  Details of the optoelectronics or data analysis · CPC title

• H04B10/07955

  Monitoring or measuring power · CPC title

• G01M11/3127

  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