Optical fiber with numerical aperture compression

• US 20020021869A1
• Filed: 06/11/2001
• Published: 02/21/2002
• Est. Priority Date: 09/01/1998
• Status: Active Grant

• Current Assignee: Boston Scientific Scimed (Boston Scientific Corporation)
• Original Assignee: Stephen Griffin
• Inventors: Griffin, Stephen
• Granted Patent: US 6,687,436 B2
• Time in Patent Office: Days
• US Class Current: 385/43
• CPC Class Codes: A61B 18/22 the beam being directed along or through a flexible conduit, e.g. an optical fibre; Couplings or hand-pieces therefor
• CPC Class Codes: A61B 18/24 with a catheter A61B18/26, A61B18/28 take precedence
• CPC Class Codes: A61B 2018/00589 Coagulation
• CPC Class Codes: A61B 2018/2205 Characteristics of fibres
• CPC Class Codes: A61B 5/0075 by spectroscopy, i.e. measuring spectra, e.g. Raman spectroscopy, infrared absorption spectroscopy A61B5/0071 takes precedence
• CPC Class Codes: A61B 90/30 Devices for illuminating a surgical field, the devices having an interrelation with other surgical devices or with a surgical procedure
• CPC Class Codes: A61C 1/088 Illuminating devices or attachments for examination of the mouth A61B1/24 and A61B1/06
• CPC Class Codes: G02B 6/2552 reshaping or reforming of light guides for coupling using thermal heating, e.g. tapering, forming of a lens on light guide ends
• CPC Class Codes: G02B 6/262 Optical details of coupling light into, or out of, or between fibre ends, e.g. special fibre end shapes or associated optical elements

Abstract

A fiber optic probe of the type typically used in medical instruments includes an illumination optical fiber having a relatively high Numerical Aperture (NA) for coupling as much light as possible into the fiber at its input end. At the output end, an outwardly flared uniform taper is proved to increase coloration of the light exiting from the illumination end, thereby causing the Numerical Aperture (NA) at the output end of the illumination fiber to be a lower NA than that at the input end. Additionally, there is a bevel cut into the end of the fiber to provide total internal reflectance whereby the source light is redirected out a side of the fiber. A sidewall face may be provided to provide for a circular rather than an elliptical illumination spot. For optical spectroscopy applications, collection fibers are located in close proximity to or surrounding the tapered output end of the illumination fiber for collecting reflected or scattered light rays from a target for use in qualitative and quantitative analysis of material.

Claims

1. A side-firing optical fiber comprising:

a tapered fiber section of a predetermined length having a light input end of a first predetermined diameter and having a light output end of a second predetermined diameter wherein the second predetermined diameter is greater than the first predetermined diameter;

said light output end further having a bevel face cut into the light output end to provide internal reflectance thereby directing the path of an incoming light beam through a sidewall of the fiber.

2. The side-firing optical fiber according to claim 1 wherein said tapered fiber section has a uniform taper from the light input end to the light output end.

3. The side-firing optical fiber according to claim 1 wherein the output end further comprises a flat cut on an output face of the sidewall of the fiber.

4. The side-firing optical fiber according to claim 2 wherein the output end further comprises a flat cut on an output face of the sidewall of the fiber.

5. The side-firing optical fiber according to claim 1 further including a material coated on the bevel face.

6. The side-firing optical fiber according to claim 2 further including a material coated on the bevel face.

7. The side-firing optical fiber according to claim 3 further including a material coated on the bevel face.

8. The side-firing optical fiber according to claim 4 further including a material coated on the bevel face.

9. A side-firing optical fiber including in combination:

a first fiber section having a light input end and a light output end and having a first predetermined diameter; and

a tapered fiber section of a predetermined length having an input end of said first predetermined diameter able to be optically coupled with the output end of said first fiber section and having a light output end of a second predetermined diameter wherein the second predetermined diameter is greater than the first predetermined diameter;

said light output end further having a bevel face cut into the light output end to provide internal reflectance thereby directing the path of an incoming light beam through a sidewall of the fiber.

10. The side-firing optical fiber according to claim 9 wherein said tapered fiber section has a uniform taper from the light input end to the light output end.

11. The side-firing optical fiber according to claim 9 wherein the output end further comprises a flat cut on an output face of the sidewall of the fiber.

12. The side-firing optical fiber according to claim 10 wherein the output end further comprises a flat cut on an output face of the sidewall of the fiber.

13. The side-firing optical fiber according to claim 9 further including a material coated on the bevel face.

14. The side-firing optical fiber according to claim 10 further including a material coated on the bevel face.

15. The side-firing optical fiber according to claim 11 further including a material coated on the bevel face.

16. The side-firing optical fiber according to claim 12 further including a material coated on the bevel face.

18. The side-firing optical fiber according to claim 17 wherein said tapered fiber section has a uniform taper from the light input end to the light output end.

19. The side-firing optical fiber according to claim 17 wherein the output end further comprises a flat cut on an output face of the sidewall of the fiber.

20. The side-firing optical fiber according to claim 18 wherein the output end further comprises a flat cut on an output face of the sidewall of the fiber.

21. The side-firing optical fiber according to claim 17 further including a material coated on the bevel face.

22. The side-firing optical fiber according to claim 18 further including a material coated on the bevel face.

23. The side-firing optical fiber according to claim 19 further including a material coated on the bevel face.

24. The side-firing optical fiber according to claim 20 further including a material coated on the bevel face.

17. A side-firing optical fiber assembly including in combination:

an illumination fiber section having a light input end and a light output end and having a first predetermined diameter;

a first tapered fiber section of a predetermined length with an input end of said first predetermined diameter optically coupled with the output end of said first fiber section, and having a light output end of a second predetermined diameter wherein the second predetermined diameter is greater than the first predetermined diameter;

said light output end further having a bevel face cut into the light output end to provide internal reflectance thereby directing the path of an incoming light beam through a sidewall of the fiber;

a collection fiber section having a light input end and a light output end, said collection fiber section physically located with the light input end thereof adjacent the light output end of said tapered fiber section, said light input end of the collection fiber section further having a bevel face cut into the light input end to provide internal reflectance thereby directing the path of an incoming light beam from a sidewall of the fiber.