STRAIN ISOLATED FIBER BRAGG GRATING SENSORS

• US 20150117810A1
• Filed: 09/26/2014
• Published: 04/30/2015
• Est. Priority Date: 10/24/2013
• Status: Active Grant

• Current Assignee: Weatherford Technology Holdings, LLC (Weatherford International PLC)
• Original Assignee: Weatherford/Lamb Incorporated (Weatherford International PLC)
• Inventors: TAVERNER, Domino, GRUNBECK, John J.
• Granted Patent: US 10,451,807 B2
• Time in Patent Office: Days
• US Class Current: 385/12
• CPC Class Codes: G01K 11/3206 at discrete locations in the fibre, e.g. using Bragg scattering
• CPC Class Codes: G02B 6/34 utilising prism or grating G02B6/293 takes precedence
• CPC Class Codes: Y10T 29/49016 Antenna or wave energy "plumbing" making

Abstract

A sensing device is used for measuring physical characteristics. The sensing device may include an optical fiber disposed in a tube. The optical fiber may have a section containing a fiber Bragg grating (FBG) sensor. A support member may be coupled to the ends of the section, such that the section includes a length greater than a length of the portion of the support member disposed between the ends of the section. The support member is configured to isolate the FBG sensor from strain in the optical fiber.

Claims

1. A sensing device, comprising:

a tube;

a first optical fiber disposed in the tube, the first optical fiber having a section containing a fiber Bragg grating (FBG) sensor; and

a support member coupled to the ends of the section, wherein the section includes a length greater than a length of the portion of the support member disposed between the ends of the section.

2. The device of claim 1, wherein the support member comprises a rigid support.

3. The device of claim 2, wherein the rigid support comprises glass.

4. The device of claim 1, wherein the support member comprise a flexible support.

5. The device of claim 4, wherein the flexible support comprises a fiber.

6. The device of claim 1, wherein the support member is part of a second optical fiber disposed in the tube, the second optical fiber containing an FBG sensor.

7. The device of claim 6, wherein the FBG sensor of the second optical fiber is isolated from strain by a support section of the first optical fiber.

8. The device of claim 6, wherein a section of the second optical fiber containing the FBG sensor is coupled to a support section of the first optical fiber, the support section of the first optical fiber having a length shorter than a length of the section of the second optical fiber containing the FBG sensor.

9. The device of claim 1, wherein the tube is formed from metal.

10. A method of forming a sensing device, comprising:

coupling a support member to the ends of a section of a first optical fiber, the section of the first optical fiber containing a fiber Bragg grating (FBG) sensor, wherein the section includes a length greater than a length of the portion of the support member disposed between the ends of the section.

11. The method of claim 10, wherein the support member comprises a rigid support.

12. The method of claim 10, wherein the support member comprise a flexible support.

13. The method of claim 10, wherein the support member is part of a second optical fiber.

14. The method of claim 13, wherein a section of the second optical fiber that contains a FBG sensor is coupled to a support section of the first optical fiber, the support section of the first optical fiber having a length shorter than a length of the section of the second optical fiber containing the FBG sensor.

15. The method of claim 10, further comprising inserting the first optical fiber into a tube.