Long distance optical fiber sensing system and method

• US 9,891,134 B2
• Filed: 12/12/2014
• Issued: 02/13/2018
• Est. Priority Date: 09/28/2009
• Status: Active Grant

• Current Assignee: AT&T Intellectual Property I LP (AT&T, Inc.)
• Original Assignee: AT&T Intellectual Property I LP (AT&T, Inc.)
• Inventors: Huffman, John Sinclair
• Primary Examiner(s): Stock, Jr., Gordon J
• Application Number:
  US14/568,439
• Publication Number:
  US 20150177096A1
• Time in Patent Office: 1,159 Days
• Field of Search: 356 731, 385 12, 385 13, 25022714-22719, 340541, 340565-567
• CPC Class Codes: G01D 5/35358 using backscattering to detect the measured quantity
• CPC Class Codes: G01D 5/35374 Particular layout of the fiber
• CPC Class Codes: G01H 9/004 using fibre optic sensors light guides per se G02B6/00, acousto-optical devices specially adapted for gating or modulating in optical wave guides G02F1/125
• CPC Class Codes: G01M 11/3109 Reflectometers detecting the back-scattered light in the time-domain, e.g. OTDR
• CPC Class Codes: G01M 11/3136 for testing of multiple fibers
• CPC Class Codes: G01S 17/04 Systems determining the presence of a target
• CPC Class Codes: G01S 17/26 wherein the transmitted pulses use a frequency-modulated or phase-modulated carrier wave, e.g. for pulse compression of received signals
• CPC Class Codes: G01S 17/88 Lidar systems specially adapted for specific applications
• CPC Class Codes: G01V 1/001 Acoustic presence detection
• CPC Class Codes: G08B 13/124 with the breaking or disturbance being optically detected, e.g. optical fibers in the perimeter fence

Abstract

A long-distance fiber optic monitoring system having a sensing unit and an analyzer that is remotely located from the sensing unit is provided. The sensing unit comprises a source of optical energy for injecting optical energy into the fiber optical cable and an optical detector configured to detect an optical return signal from the optical fiber. The detected optical return signal is associated with an acoustic signal impinging on the optical fiber. The analyzer receives a signal from the remote sensing unit via the optical fiber that is representative of the optical return signal, and determines a location of a disturbance based at least on the received signal. The representative signal can be transmitted from the remote sensing unit to the analyzer as an optical signal or via a metallic wired included with the optical fiber.

Claims

1. A method comprising:

receiving, from a remote sensing unit comprising an optical detector, a signal representative of a plurality of features of a first optical return signal associated with acoustic disturbances impinging upon a first optical fiber of a plurality of optical fibers having an overlapping point; and

determining locations of the acoustic disturbances impinging upon the optical fiber associated with a source disturbance, at a plurality of times, based on analysis of the signal representative of the first optical return signal and a signal representative of a plurality of features of a second optical return signal associated with the acoustic disturbances impinging on a second one of the plurality of optical fibers having an overlapping point.

2. The method of claim 1, wherein the first optical fiber is arranged in a multi-dimensional layout.

3. The method of claim 1, further comprising:

generating an alert based on determining a specific location of an acoustic disturbance.

4. The method of claim 3, wherein the specific location is within a certain perimeter from the first optical fiber.

5. The method of claim 1, the method further comprising:

determining a path of travel and a velocity of motion of the source disturbance based on the locations determined.

6. The method of claim 1, wherein the signal representative of the first optical return signal is received as an encoded signal comprising a wavelength.

7. The method of claim 1, wherein the first optical return signal is affected by the acoustic disturbances impinging upon the first optical fiber.

8. An apparatus comprising:

a processor; and

a memory to store computer program instructions, the computer program instructions when executed on the processor cause the processor to perform operations comprising;

receiving, from a remote sensing unit comprising an optical detector, a signal representative of a plurality of features of a first optical return signal associated with acoustic disturbances impinging upon a first optical fiber of a plurality of optical fibers having an overlapping point; and

determining locations of the acoustic disturbances impinging upon the optical fiber associated with a source disturbance, at a plurality of times, based on analysis of the signal representative of the first optical return signal and a signal representative of a plurality of features of a second optical return signal associated with the acoustic disturbances impinging on a second one of the plurality of optical fibers having an overlapping point.

9. The apparatus of claim 8, wherein the first optical fiber is arranged in a multi-dimensional layout.

10. The apparatus of claim 8, the operations further comprising:

generating an alert based on determining a specific location of an acoustic disturbance.

11. The apparatus of claim 10, wherein the specific location is within a certain perimeter from the first optical fiber.

12. The apparatus of claim 8, the operations further comprising:

determining a path of travel and a velocity of motion of the source disturbance based on the locations determined.

13. The apparatus of claim 8, wherein the signal representative of the first optical return signal is received as an encoded signal comprising a wavelength.

14. The apparatus of claim 8, wherein the first optical return signal is affected by the acoustic disturbances impinging upon the first optical fiber.

15. A computer readable storage device storing computer program instructions, which, when executed on a processor, cause the processor to perform operations comprising:

receiving, from a remote sensing unit comprising an optical detector, a signal representative of a plurality of features of a first optical return signal associated with acoustic disturbances impinging upon a first optical fiber of a plurality of optical fibers having an overlapping point; and

determining locations of the acoustic disturbances impinging upon the optical fiber associated with a source disturbance, at a plurality of times, based on analysis of the signal representative of the first optical return signal and a signal representative of a plurality of features of a second optical return signal associated with the acoustic disturbances impinging on a second one of the plurality of optical fibers having an overlapping point.

16. The computer readable storage device of claim 15, wherein the first optical fiber is arranged in a multi-dimensional layout.

17. The computer readable storage device of claim 15, the operations further comprising:

generating an alert based on determining a specific location of an acoustic disturbance.

18. The computer readable storage device of claim 17, wherein the specific location is within a certain perimeter from the first optical fiber.

19. The computer readable storage device of claim 15, the operations further comprising:

determining a path of travel and a velocity of motion of the source disturbance based on the locations determined.

20. The computer readable storage device of claim 15, wherein the signal representative of the first optical return signal is received as an encoded signal comprising a wavelength.