Segmented fiber optic sensor and method

• US 20070065075A1
• Filed: 09/22/2005
• Published: 03/22/2007
• Est. Priority Date: 09/22/2005
• Status: Active Grant

• Current Assignee: Optech Ventures, LLC
• Original Assignee: Intelligent Optical Systems, Inc.
• Inventors: Berger, Alexander, Lieberman, Robert
• Granted Patent: US 7,551,810 B2
• Time in Patent Office: Days
• US Class Current: 385/37
• CPC Class Codes: G01J 3/02 Details
• CPC Class Codes: G01J 3/0218 using optical fibers
• CPC Class Codes: G01N 2021/7716 in cladding
• CPC Class Codes: G01N 2021/7779 interferometric
• CPC Class Codes: G01N 2021/7783 Transmission, loss
• CPC Class Codes: G01N 21/7703 using reagent-clad optical fibres or optical waveguides using measurement of total internal reflection or attenuated total reflection G01N21/552; optical fibres or waveguides per se G02B
• CPC Class Codes: G01N 21/78 producing a change of colour
• CPC Class Codes: G01N 2201/0833 Fibre array at detector, resolving
• CPC Class Codes: G01N 2201/088 Using a sensor fibre
• CPC Class Codes: G02B 6/441 built up from sub-bundles G02B6/4429, G02B6/4439, G02B6/4479 take precedence
• CPC Class Codes: G02B 6/4434 Central member to take up tensile loads

Abstract

A fiber optic sensor for sensing the presence of an analyte has a plurality of optical fibers each of which has at least one analyte sensing segment and one or more low loss lead portion, where the optical fibers are disposed on the periphery of a fiber carrier. The analyte sensing segments may be disposed in an offset relationship to provide continuous detection over a desired distance or they may be spaced apart to provide detection at selected locations. More than one set of optical fibers with sensing segments may be combined to provide detection of multiple analytes. Multiple fiber carriers allow each segment or the grouped sets of segments to be coupled together over a distance either in offset relationship or in spaced apart relationship.

Claims

1. An analyte sensing apparatus comprising;

a segmented optical fiber assembly comprising;

an optical fiber carrier portion adapted to carry thereon a plurality of optical fibers peripherally lengthwise; and

a segmented optical fiber analyte set portion comprising a plurality of optical fibers carried peripherally lengthwise on the optical fiber carrier portion, each optical fiber comprising a sensing segment and at least one lead portion, wherein each sensing segment of the segmented optical fiber analyte set portion senses a same analyte.

2. The apparatus of claim 1 further comprising;

an optical energy source portion disposed to transmit light into the plurality of optical fibers; and

an optical energy detector portion coupled to the plurality of optical fibers to receive light that has passed through the respective analyte sensing segments from the plurality of optical fibers.

3. The apparatus of claim 1 further comprising a processing and reporting portion coupled to the optical fibers and adapted to determine change in optical energy passed through any of the segments that have been exposed to the analyte to which the segments are responsive and to enable an operator to determine a location of the exposure .

4. The apparatus of claim 1 wherein the segmented optical fiber analyte set comprises discrete lengths of optical fibers connected at terminal ends of the fiber carriers by a coupling means to form continuous optical paths and the carrier portion comprises a set of separate carriers disposed lengthwise to carry the discrete lengths of optical fibers between coupling means and the sensing segment of each fiber is carried on one of the separate carriers on which only lead portions of the other fibers are carried.

5. The apparatus of claim 4 wherein the relationship of sensing segments is selected from the group consisting of;

(a) offset, whereby sensing segments of fibers are disposed in sequentially disposed fiber carriers;

(b) spaced apart, whereby sensing segments of fibers are disposed on fiber carriers with one or more intermediate fiber carriers knowing only lead segments carried thereon; and

(c) a combination of off set and spaced apart.

6. The apparatus of claim 1 wherein the optical fiber carrier portion has a plurality of longitudinal slots in its periphery and the optical fibers are carried in the slots.

7. The apparatus of claim 1 further comprising a plurality of said segmented optical fiber assemblies extending in a bundle, wherein the segmented optical fiber analyte set portions of each segmented fiber assembly are configured to sense different particular analytes and

wherein the particular analyte differs from one segmented optical fiber assembly to another segmented optical fiber assembly.

8. The apparatus of claim 1 further comprising;

a covering having openings therein disposed around the periphery of the optical fiber carrier wherein the covering retains the plurality of optical fibers in place on the fiber carrier and allows passage of an analyte to contact the sensing segment.

9. The apparatus of claim 1 wherein the optical fiber carrier portion has slots along its periphery and each optical fiber is carried in a slot.

10. The apparatus of claim 1 wherein the length of each of the sensing segments in the segmented optical fiber assembly is the same.

11. The apparatus of claim 7 further comprising an elongate central core member and the plurality of segmented optical fiber assemblies are disposed around a central core member.

12. The apparatus of claim 7 further comprising;

an optical energy source disposed to transmit light into the plurality of optical fibers; and

an optical energy detector coupled to the plurality of optical fibers to receive light that has passed through the respective sensing segments from the plurality of optical fibers said detector portion being adapted to identify the light from each optical fiber.

13. The apparatus of claim 10 further comprising a plurality of the segmented optical fiber assemblies and a wrapping disposed around the plurality of segmented optical fiber assemblies, wherein the covering holds the plurality of optical fiber assemblies against a central core member, whereby the wrapping allows the sensing segments to be exposed.

14. The apparatus as claimed in claim 12 wherein the optical energy source and the optical energy detector are coupled to proximal ends of the plurality of optical fibers with one or more optical circulators and reflective elements are disposed at distal ends of the plurality of optical fibers.

15. The apparatus as claimed in claim 12 wherein the optical energy source is disposed at proximal ends of the plurality of optical fibers and the optical energy detector is disposed at distal ends of the plurality of optical fibers.

16. The apparatus as claimed in claim 12 wherein the optical energy source is selected from the group consisting of:

a plurality of light sources;

one or more light sources and one or more optical splitters coupled to the one or more light sources; and

one or more light sources and one or more optical splitters coupled to receive light from the one or more light sources and a plurality of optical switches coupled to the one or more optical splitters to receive light from the one or more optical splitters.

17. The apparatus as claimed in claim 12 wherein the optical energy detector comprises:

a plurality of light detectors, or one or more optical combiners and one or more light detectors disposed to receive light from the one or more optical combiners.

18. The apparatus as claimed in claim 12 further comprising one or more reference fibers and the optical energy source comprises one or more coherent light sources coupled to at least one light source splitter, wherein the at least one light source splitter transmits light to the plurality of optical fibers and the one or more reference fibers, and the optical energy detector comprises:

a plurality of light detectors;

a plurality of optical combiners, each optical combiner having an output coupled to a corresponding one light detector of the plurality of light detectors, a first input coupled to a corresponding one optical fiber of the plurality of optical fibers, and a second input disposed to receive light from the one or more reference fibers; and

one or more reference fiber splitters coupled to receive light from the one or more reference fibers and to transmit light to the second inputs of the optical combiners.

19. The apparatus as claimed in claim 12 wherein the optical energy source comprises one or more coherent light sources coupled to at least one light source splitter and the at least one light source splitter transmits light to the plurality of optical fibers and the optical energy detector comprises a plurality of light detector and optical combiner combinations, wherein the optical combiner of each combination has a first input coupled to a first optical fiber of the plurality of optical fibers and a second input coupled to a second optical fiber of the plurality of optical fibers and an output coupled to a light detector.

20. The apparatus as claimed in claim 12 wherein the one or more one sensing segments are disposed to sense an analyte within different defined areas and the optical energy source and the optical energy detector are coupled to a processor, wherein the processor produces an output based on the detection of an analyte within the defined areas.

21. The apparatus as claimed in claim 14 wherein the optical energy source comprises a plurality of light sources, at least one light source for each optical fiber, and the optical energy detector comprises a plurality of photodetectors, at least one photodetector for each optical fiber, and each optical fiber has at least one light source and at least one photodetector coupled to the proximal end of the optical fiber through one of the one or more optical circulators.

22. The apparatus as claimed in claim 14 wherein the optical energy source comprises one or more light sources and the optical energy detector comprises one or more photodetectors and one or more optical switches couple the one or more optical circulators to the proximal ends of the plurality of optical fibers.

23. The apparatus as claimed in claim 19 wherein the first optical fiber and the second optical fiber have sensing segments that are not adjacent and are not overlapping.

24. A method for sensing the presence of one or more analytes, the method comprising;

providing a plurality of fiber carriers wherein each fiber carrier has a central axis;

disposing one or more optical fiber analyte-sensing segments on a portion of a periphery of each fiber carrier parallel to the central axis of each fiber carrier;

disposing one or more optical fiber lead portions on other portions of the periphery of each fiber carrier parallel to the central axis of the fiber carrier; and

disposing the plurality of fiber carriers around an elongate central core having a central axis, wherein the plurality of fiber carriers are disposed parallel to the central axis of the central core.

25. The method as claimed in claim 24 wherein the optical fiber lead portions comprise low attenuation optical fiber.

26. The method as claimed in claim 24 wherein the optical fiber analyte-sensing segments and the optical fiber lead portions comprise a plurality of optical fibers disposed lengthwise adjacently and each optical fiber has one optical fiber analyte-sensing segment and the optical fiber analyte-sensing segment of each optical fiber is offset from the optical fiber analyte-sensing segments of the adjacent optical fibers to provide a continuous analyte-sensing length over a desired distance.

27. The method as claimed in claim 24 wherein the optical fiber analyte-sensing-segments and the optical fiber lead portions comprise a plurality of optical fibers disposed lengthwise adjacently, wherein each optical fiber has one analyte-sensing segment and the analyte-sensing segment of each optical fiber are linearly spaced apart from the analyte-sensing segments of the adjacent optical fibers, whereby there is a non-analyte-sensing gap between the adjacent optical fiber analyte-sensing segments.

28. The method as claimed in claim 24 further comprising detecting changes in light propagating through the optical fiber analyte-sensing segments with at least one interferometer.

29. The method as claimed in claim 24 further comprising bundling the optical fiber analyte-sensing segments and the optical fiber lead portions into a single fiber bundle.

30. The method as claimed in claim 24 wherein the method further comprises;

receiving optical energy at a proximal end of at least one of the optical fiber analyte-sensing segments; and

disposing a reflective element at a distal end of the at least one optical fiber analyte-sensing segment.

31. The method as claimed in claim 24 wherein the method further comprises;

receiving optical energy at a proximal end of at least one of the optical fiber analyte-sensing segments;

coupling a proximal end of a non-analyte-sensing optical fiber segment to a distal end of the at least one optical fiber analyte-sensing segment; and

disposing a reflective element at a distal end of the non-analyte-sensing optical fiber segment.

32. The method as claimed in claim 24 wherein the optical fiber analyte-sensing segments are placed within defined areas and the method further comprises;

transmitting optical energy into the optical fiber analyte-sensing segments;

receiving optical energy from the optical fiber analyte-sensing segments; and

processing the received optical energy to determine detection of at least one analyte within any of the defined areas.

33. The method as claimed in claim 26 wherein the number of optical fibers in the plurality of optical fibers equals N and the desired distance equals L and each optical fiber analyte-sensing segment has a length equal to L/N.

34. An analyte sensing apparatus comprising;

a plurality of optical fibers disposed lengthwise adjacently in one or more fiber carriers, each optical fiber of the plurality of optical fibers comprising;

one or more analyte responsive segments and

one or more lead portions;

means for providing optical energy to the optical fibers; and

means for detecting optical energy propagating within the optical fibers, wherein the analyte responsive segments are disposed at desired locations and wherein the one or more fiber carriers comprise one or more cylindrical fiber carriers having slots disposed on peripheries of the one or more cylindrical fiber carriers in directions parallel to central axes of the one or more cylindrical fiber carriers and wherein at least one analyte responsive segment of at least one optical fiber is disposed in one slot of at least one cylindrical fiber carrier and at least one lead segment of another optical fiber is disposed in another slot of the at least one cylindrical fiber carrier.

35. The apparatus according to claim 34 wherein each optical fiber has one analyte responsive segment and the analyte responsive segments are disposed to provide a continuous analyte-sensing length over a desired distance.

36. The apparatus according to claim 34 wherein the one or more analyte-responsive segments of each optical fiber are disposed in a non-adjacent and non-overlapping manner to detect analytes at different and discrete locations.

37. The apparatus as claimed in claim 34 wherein the means for providing optical energy is disposed at proximal ends 6f the plurality of optical fibers and the means for detecting optical energy is disposed at distal ends of the plurality of optical fibers.

38. The apparatus as claimed in claim 34 wherein the means for providing optical energy and the means for deleting optical energy are disposed at proximal ends of the plurality of optical fibers.