Lightwave communication monitoring system

• US 5,790,285 A
• Filed: 05/21/1996
• Issued: 08/04/1998
• Est. Priority Date: 05/21/1996
• Status: Expired due to Term

• Current Assignee: Lucent Technologies, Inc. (Nokia Corporation)
• Original Assignee: Lucent Technologies, Inc. (Nokia Corporation)
• Inventors: Mock, Joel Leslie
• Primary Examiner(s): NEGASH, KINFE MICHAEL
• Application Number:
  US08/651,945
• Time in Patent Office: 805 Days
• Field of Search: 359/110, 359/124, 359/127, 359/173, 359/177, 356/73.1
• US Class Current: 398/21
• CPC Class Codes: H04B 10/07 Arrangements for monitoring or testing transmission systems; Arrangements for fault measurement of transmission systems
• CPC Class Codes: H04B 10/077 using a supervisory or additional signal
• CPC Class Codes: H04B 10/07955 Monitoring or measuring power
• CPC Class Codes: H04Q 11/0062 Network aspects
• CPC Class Codes: H04Q 2011/0049 Crosstalk reduction; Noise; Power budget
• CPC Class Codes: H04Q 2011/0083 Testing; Monitoring

Abstract

A lightwave communication monitoring system has a monitoring member to which are applied signals extracted from one or more fibers in a transmission system. The monitoring member detects the signal and applies a signal derived therefrom to a control or processing unit. When the strength of the derived signal is below a predetermined minimum, the control unit is adapted to activate a fault location member which applies a fault location signal to the fiber circuit in which the signal, or lack thereof, is transmitted. The system is capable of handling a plurality o fiber circuits simultaneously. In another embodiment of the invention, a test signal is launched on the first fiber, or, simultaneously launched on a plurality of first fibers of fiber pairs, and the test signal is simultaneously extracted from one or more of a plurality of corresponding second fibers of the fiber pairs. The system also includes means for measuring the strength of the transmission signals, which are at a different frequency from the test signal.

Claims

1. An optical fiber monitoring system for continuously monitoring the condition of optical fibers comprising:

a plurality of individual means for extracting optical energy from a plurality of optical fibers, each of said means being adapted to extract optical energy from one fiber of the plurality of optical fibers;

means for applying the extracted energy to a monitoring means comprising a monitoring fiber extending from each of said individual means for extracting and having a fiber termination in said monitoring means, said monitoring means including means for responding to the presence of the optical energy for generating a signal indicative of the optical energy level;

measuring means for receiving the signal thus generated for ascertaining when the optical energy indicates an optical fiber fault;

locating means under control of said measuring means for generating a fault locating signal; and

means for launching the fault locating signal on to the optical fiber.

2. An optical fiber monitoring system as claimed in claim 1 wherein said termination of each of said monitoring fibers includes means for forming optical energy emerging from said terminations.

3. An optical fiber monitoring system as claimed in claim 2 wherein said monitoring means has a plurality of light devices spaced from said fiber termination, each one of said light devices being aligned with one of said fiber terminations for receiving optical energy emerging therefrom.

4. An optical fiber monitoring system as claimed in claim 1 wherein said means for responding comprises at least one photodetector.

5. An optical fiber monitoring system as claimed in claim 1 wherein said locating means comprises a reflectometer.

6. An optical fiber monitoring system as claimed in claim 1 wherein said means for launching the fault locating signal comprises an optical fiber having a terminated end and a second end connected to said locating means for transmitting the fault locating signal.

7. An optical fiber monitoring system as claimed in claim 6 wherein said terminated end is adapted to be positioned adjacent to and spaced from said means for applying the extracted energy for applying the directing energy therethrough to the optical fiber.

8. An optical fiber monitoring system for continuously monitoring the condition of optical fibers comprising:

a monitoring member;

means for generating a test signal and passing it through said monitoring member;

first means for applying the test signal to a first optical fiber of an optical fiber pair;

second means remote from said first means for extracting the test signal from the first optical fiber;

third means for receiving the signal extracted by said second means for applying it to the second optical fiber of the optical fiber pair;

fourth means remote from said third means for extracting the test signal from the second optical fiber and applying it to the monitoring member;

means responsive to the optical signal applied to said monitoring means for generating a signal indicative of the optical signal level;

measuring means for receiving the signal thus generated for ascertaining when the optical energy indicates an optical fiber fault;

locating means under control of said measuring means for generating a fault locating signal when said measuring means detects an optical fiber fault in one of the first and second fibers of the optical fiber pair; and

means for launching the fault locating signal on to the one optical fiber.

9. An optical fiber monitoring system as claimed in claim 8 and further including means for blocking the test signal from one of the fibers under test when the fault locating signal is launched on to the other fiber of the fiber pair.

10. An optical fiber monitoring system as claimed in claim 8 wherein at least one of said first, second, third and fourth means is a wavelength division multiplexer.

11. An optical fiber monitoring system as claimed in claim 8 wherein each of said first, second, third and fourth means is a wavelength division multiplexer.

12. An optical fiber monitoring system as claimed in claim 8 wherein there is a plurality of groups comprising said first, second, third, and fourth means, each one of said groups being adapted to function with a single fiber pair.

13. An optical fiber monitoring system as claimed in claim 12 wherein said monitoring member includes means for simultaneously applying the test signal to the first fiber of each of a plurality of fiber pairs.

14. An optical fiber monitoring system as claimed in claim 12 wherein said monitoring member includes a plurality of said means responsive to the optical signal applied to said monitoring means from said fourth means.

15. An optical fiber monitoring system as claimed in claim 8 wherein the optical fibers being monitored are adapted to transmit optical signals in a first frequency band, and said test signal is in a second different frequency band.

16. An optical fiber monitoring system as claimed in claim 15 and further including means for measuring the optical signal strength of signals at the first frequency.

17. A method of continuously monitoring the condition of optical fibers adapted to transmit signals in a first frequency band comprising the steps of

extracting an optical signal from a fiber being monitored;

directing and applying the signal to a monitoring member by means of a fiber member having a light emitting termination in the monitoring member;

detecting the light or absence thereof emerging from the termination and generating a monitor signal indicative of the energy thereof;

applying the monitor signal to a power measuring device to generate a control signal when the monitor signal indicates a fault in the fiber because of insufficient light emerging from the termination;

applying the control signal to a fault locating means for generating a fault location signal; and

selectively applying the fault location signal to the fiber termination having insufficient light emerging therefrom.

18. The method as claimed in claim 17 wherein the step of extracting an optical signal comprises simultaneously extracting a signal from each of a plurality of fibers being monitored.

19. The method as claimed in claim 18 wherein the step of directing and applying the signal to a monitoring member comprises simultaneously directing and applying the signal from each of the plurality of fibers to the monitoring member.

20. The method as claimed in claim 19 wherein the step of detecting the light emerging from the termination comprises simultaneously detecting the light emerging from the termination of each of a plurality of terminations in the monitoring means.

21. A method of continuously monitoring the condition of optical fiber pairs adapted to transmit signals in a first frequency band comprising the steps of

generating a test signal in a frequency band different from the frequency band of the transmission signals in the fiber pairs;

applying the test signal to the first fiber of the fiber pair at a first location thereon;

extracting the test signal from the first fiber at a second location removed from the first location;

applying the extracted test signal to the second fiber of the fiber pair substantially at the second location;

extracting the test signal from the second fiber substantially at the first location and applying it to a monitoring member;

detecting and measuring the strength of the test signal and generating a first control signal when the strength of the detected test signal is insufficient;

generating a fault location signal by means of the control signal; and

applying the fault location signal to the second fiber of the fiber pair.

22. The method as claimed in claim 21 and further including the step of blocking the test signal from the first fiber of the optical fiber pair when applying the fault location signal to the second fiber of the pair.

23. A method as claimed in claim 22 and further including the step of measuring the strength of the signal in the first frequency band transmitted by the fiber pair.

24. The method as claimed in claim 22 wherein the step of applying the test signal to the first fiber of a pair comprises simultaneously applying the test signal to each of a plurality of first fibers of a plurality of fiber pairs.

25. The method as claimed in claim 24 wherein the steps of extracting the test signal from the first fiber and applying it to the second fiber of the fiber pair comprises simultaneously extracting the signals from a plurality of first fibers and applying the signals to a plurality of corresponding second fibers.

26. The method as claimed in claim 25 wherein the step of applying the signal to a monitoring member comprises simultaneously applying the signals from a plurality of second fibers to the monitoring member.

27. A method as claimed in claim 26 wherein the step of detecting and measuring the strength of the test signal comprises simultaneously detecting and measuring signals from a plurality of second fibers of the fiber pairs.

28. An optical fiber monitoring system for continuously monitoring the condition of one or more optical fibers comprising:

means for extracting a portion of the optical energy from an optical energy bearing optical fiber;

means for applying the extracted energy to a monitoring means, said monitoring means including means for responding to the presence of the optical energy for generating a signal indicative of the optical energy level;

measuring means for receiving the signal thus generated for ascertaining when the optical energy indicates an optical fiber fault and identifying the fiber having the fault;

locating means under control of said measuring means for generating a fault locating signal; and

means for selectively launching the fault locating signal on to the fiber having the fault to the exclusion of other fibers.

29. An optical fiber monitoring system as claimed in claim 28 wherein said means for extracting optical energy comprises a plurality of individual extracting means, each of said individual extracting means being adapted to extract optical energy from one of a plurality of optical fibers.