Optical waveguide sensors

• US 6,360,031 B1
• Filed: 08/24/1999
• Issued: 03/19/2002
• Est. Priority Date: 08/24/1999
• Status: Expired due to Fees

• Current Assignee: Adherent Technologies, Inc.
• Original Assignee: Adherent Technologies, Inc.
• Inventors: Harrah, Larry A.
• Primary Examiner(s): NGO, HUNG NHAT
• Application Number:
  US09/379,706
• Time in Patent Office: 938 Days
• Field of Search: 385/12, 385/127, 385/38
• US Class Current: 385/12
• CPC Class Codes: G01N 2021/7706 Reagent provision
• CPC Class Codes: G01N 2021/7716 in cladding
• CPC Class Codes: G01N 2021/772 Tip coated light guide
• 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: G02B 6/02033 Core or cladding made from organic material, e.g. polymeric material G02B1/04 takes precedence
• CPC Class Codes: G02B 6/03622 having 2 layers only
• CPC Class Codes: G02B 6/03694 Multiple layers differing in properties other than the refractive index, e.g. attenuation, diffusion, stress properties

Abstract

An optical waveguide sensor using an intermediate layer between the preformed optical core and the optical cladding material. This intermediate layer comprises a material that is doped with a sensor material to respond to an analyte of interest by luminescing or by developing optical absorption in the transmission region of the core fiber and that has a refractive index greater than the preformed core. Two configurations provide sensors for ionizing radiation capable of measuring the dose rate and the integrated deposited dose.

Claims

1. An optical waveguide sensor comprising:

a waveguide core;

a reflective cladding; and

at least one intermediate layer positioned between said waveguide core and said reflective cladding wherein said at least one intermediate layer comprises a material responsive to at least one environmental stimulus selected from the group consisting of ultraviolet radiation and ionizing radiation; and

wherein refractive indices of said core (n₁), said at least one intermediate layer (n₂) and said reflective cladding (n₃) obey the relationship n₂≧

n₁>

n₃.

2. The waveguide sensor of claim 1 wherein said material responsive to at least one environmental stimulus comprises a dye that changes optical absorption characteristics upon exposure to ionizing radiation.

3. The waveguide sensor of claim 2 wherein said sensor comprises a radiation dosimeter.

4. The waveguide sensor of claim 1 wherein said sensor comprises a segment of a waveguide wherein said waveguide comprises the waveguide core and a reflective cladding.

5. The waveguide sensor of claim 1 wherein said sensor comprises a terminal end of a waveguide wherein said waveguide comprises a waveguide core comprising a terminal end and a reflective cladding.

6. The waveguide sensor of claim 5 additionally comprising a reflective cap and at least one intermediate layer positioned between said terminal end of said waveguide core and said reflective cap.

7. An optical waveguide sensor comprising:

a waveguide core comprising an outer surface; and

a layer positioned on said outer surface of said waveguide core wherein said layer comprises a material responsive to at least one environmental stimulus selected from the group consisting of ultraviolet radiation and ionizing radiation.

8. The optical waveguide of claim 7 wherein said layer comprises an outer surface and said outer surface contacts a medium comprising a refractive index greater than the refractive index of said waveguide core.

9. The waveguide sensor of claim 7 wherein said material responsive to at least one environmental stimulus comprises a dye that changes optical absorption characteristics upon exposure to ionizing radiation.

10. The waveguide sensor of claim 9 wherein said sensor comprises a radiation dosimeter.

11. The waveguide sensor of claim 7 wherein said sensor comprises a segment of a waveguide.

12. The waveguide sensor of claim 7 wherein said sensor comprises a terminal end of a waveguide.

13. The waveguide sensor of claim 12 comprising at least one intermediate layer positioned adjacent to said terminal end.

14. A method for fabricating an optical waveguide sensor comprising the steps of:

a) providing a waveguide core having an outer surface; and

b) affixing an intermediate layer to the outer surface of the waveguide core wherein the intermediate layer comprises a material responsive to at least one environmental stimulus selected from the group consisting of ultraviolet radiation and ionizing radiation.

15. The method of claim 14 further comprising the step of affixing a reflective cladding to the outer surface of the intermediate layer.

16. The method of claim 14 wherein the affixing step comprises providing a material responsive to at least one environmental stimulus comprising a dye that changes optical absorption characteristics upon exposure to ionizing radiation.

17. The method of claim 16 wherein the sensor is a radiation dosimeter.

18. The method of claim 14 wherein the providing step comprises providing a segment of a waveguide wherein the waveguide comprises the waveguide core and a reflective cladding.

19. The method of claim 14 wherein the providing step comprises providing a terminal end of a waveguide wherein the waveguide comprises a waveguide core comprising a terminal end and a reflective cladding.

20. The method of claim 19 wherein the providing step further comprises providing a reflective cap and at least one intermediate layer positioned between the terminal end of the waveguide core and the reflective cap.