Optical fiber illumination systems and methods

• US 8,545,076 B2
• Filed: 08/19/2011
• Issued: 10/01/2013
• Est. Priority Date: 11/20/2009
• Status: Expired

• Current Assignee: Corning Incorporated
• Original Assignee: Corning Incorporated
• Inventors: Bickham, Scott Robertson, Bookbinder, Dana Craig, Fewkes, Edward John, Logunov, Stephan Lvovich
• Primary Examiner(s): CARIASO, ALAN B
• Application Number:
  US13/213,363
• Publication Number:
  US 20110305035A1
• Time in Patent Office: 774 Days
• Field of Search: 362/552, 362/558, 362/84, 362/260, 362/551, 385/122, 385/901
• US Class Current: 362/558
• CPC Class Codes: C03C 13/045 Silica-containing oxide glass compositions
• CPC Class Codes: C03C 25/105 Organic claddings
• CPC Class Codes: C03C 25/106 Single coatings
• CPC Class Codes: C03C 25/475 containing colouring agents
• CPC Class Codes: G02B 6/0003 the light guides being doped with fluorescent agents
• CPC Class Codes: G02B 6/001 the light being emitted along at least a portion of the lateral surface of the fibre
• CPC Class Codes: G02B 6/0229 characterised by nanostructures, i.e. structures of size less than 100 nm, e.g. quantum dots
• CPC Class Codes: G02B 6/02347 Longitudinal structures arranged to form a regular periodic lattice, e.g. triangular, square, honeycomb unit cell repeated throughout cladding
• CPC Class Codes: G02B 6/02361 Longitudinal structures forming multiple layers around the core, e.g. arranged in multiple rings with each ring having longitudinal elements at substantially the same radial distance from the core, having rotational symmetry about the fibre axis
• CPC Class Codes: G02B 6/02366 Single ring of structures, e.g. "air clad"

Abstract

An illumination system generating light having at least one wavelength within 200 nm a plurality of nano-sized structures (e.g., voids). The optical fiber coupled to the light source. The light diffusing optical fiber has a core and a cladding. The plurality of nano-sized structures is situated either within said core or at a core-cladding boundary. The optical fiber also includes an outer surface. The optical fiber is configured to scatter guided light via the nano-sized structures away from the core and through the outer surface, to form a light-source fiber portion having a length that emits substantially uniform radiation over its length, said fiber having a scattering-induced attenuation greater than 50 dB/km for the wavelength(s) within 200 nm to 2000 nm range.

Claims

1. A light diffusing optical fiber having an outer surface, said fiber comprising:

(i) a glass core, comprising

(a) a region with a plurality of nano-sized structures within said core configured to scatter guided light via said nano-sized structures towards the outer surface, such that said light diffusing optical fiber has a scattering-induced attenuation greater than 50 dB/km at illumination wavelength; and

(b) a solid glass region surrounding said region with a plurality of nano-sized structures having a higher refractive index delta than the region with a plurality of nano-sized structures; and

(ii) a low index cladding surrounding said core, said cladding having a lower refractive index delta than said solid glass region.

2. The light diffusing optical fiber according to claim 1, wherein said low index cladding has a refractive index delta of less than −

0.5% relative to silica.

3. The light diffusing optical fiber according to claim 1, wherein said low index cladding is glass.

4. The light diffusing optical fiber according to claim 1, wherein said low index cladding is a polymer.

5. The light diffusing optical fiber according to claim 4, wherein said low index cladding is:

(i) silicone based;

or (ii) a fluoroacrylate.

6. The light diffusing optical fiber according to claim 4, wherein said low index cladding is a fluorinated cladding.

7. The light diffusing optical fiber according to claim 1, further including phosphorus containing coating surrounding said cladding.

8. The light diffusing optical fiber of claim 1, said fiber core further having:

(i) a core diameter greater than 50 μ

m and less than 500 μ

m; and

/or (ii) numerical aperture NA, wherein NA>

0.2.

9. The light diffusing optical fiber of claim 1, wherein said nano-sized structures are gas filled voids with diameter of greater than 10 nm.

10. A cable assembly of multiple fibers of claim 9 further comprising collections of multiple ribbons, or fibers gathered into a tube.

11. The light diffusing optical fiber of claim 1, said plurality of nano-sized structures is the nano-structured region that has a width of at least 7 μ

m; and

wherein said cladding diameter is at least 125 μ

m.

12. The light diffusing optical fiber of claim 1, wherein said core has an outer diameter Rc, said core includes:

(i) a solid inner core section with an outer diameter R₁, such that 0.05Rc>

R₁>

0.9Rc;

(ii) nano-structured region having a width W₂ wherein 0.05Rc>

W₂>

0.9Rc; and

(iii) outer solid core region having a width between 0.1Rc>

Ws>

0.9Rc, wherein each section of said core comprises silica glass.

13. The light diffusing optical fiber of claim 12, said cladding comprises a low index polymer cladding surrounding core;

and a polymer coating surrounding said cladding, said polymer coating.

14. The light diffusing optical fiber of claim 1, wherein said fiber is configured to be capable of guiding said light such that radiation out of said outer surface is substantially uniform, such that the difference between the minimum and maximum scattering illumination intensity is less than 30% of the maximum scattering illumination intensity.

15. The light diffusing optical fiber of claim 1, wherein said fiber having scattering-induced attenuation is 100 dB/km to 6000 dB/km at illumination wavelength.

16. The fiber bundles or ribbons comprising multiple light diffusing fibers according to claim 1.

17. The fiber bundles or ribbons of claim 16 containing 2-36 light diffusing fibers.

18. The light diffusing optical fiber comprising:

a core, a cladding, and a plurality of nano-sized structures situated within said core or at a core-cladding boundary, said optical fiber further including an outer surface and is configured to (i) scatter guided light via said nano-sized structures away from the core and through the outer surface, (ii) have a scattering-induced attenuation greater than 50 dB/km at illumination wavelength; and

said fiber including at least one coating such that either said cladding or said at least one coating includes phosphor or pigments,

wherein said nano-sized structures are situated within one region of said core, and said core further comprises a second region without the microstructures adjacent and surrounding the region that comprises nano-sized structures;

said fiber further comprising a low index polymer cladding surrounding said second region; and

said at least one coating is a polymer coating surrounding said cladding, said polymer coating having a higher refractive index than said a low index polymer cladding.

19. The light diffusing optical fiber of claim 18, wherein said coating includes phosphorus.

20. A light diffusing optical fiber having an outer surface, said fiber comprising:

(i) a glass core, comprising

(a) a region with a plurality of nano-sized structures configured to scatter guided light via said nano-sized structures away from the core and towards the outer surface, such that said light diffusing optical fiber has a scattering-induced attenuation greater than 200 dB/km at illumination wavelength; and

(b) a solid glass region surrounding said region with a plurality of nano-sized structures having a higher refractive index delta than the region with a plurality of nano-sized structures; and

(ii) a low index cladding surrounding said core, said cladding having a lower refractive index delta than said solid glass region and is negative relative to silica;

(iii) a coating surrounding said cladding;

wherein said coating or cladding includes phosphorus.

21. The light diffusing optical fiber of claim 20, wherein the scattering loss is uniform in angular space.

22. The light diffusing optical fiber of claim 21, wherein said low index polymer cladding has a relative refractive index delta with respect to silica that is less than −

0.5%.

23. The light diffusing optical fiber of claim 21, wherein said fiber provides illumination;

and uniformity of illumination along the fiber length is with 30% from maximum intensity.

24. The light diffusing optical fiber of claim 21 wherein said nanostructures are voids filled with gas.

25. The light diffusing optical fiber of claim 20, wherein said fiber has a scattering-induced attenuation not less than 500 dB/km at the illumination wavelength.

26. The light diffusing optical fiber of claim 20, wherein said fiber has a scattering-induced attenuation greater than 1000 dB/km at illumination wavelength.

27. The light diffusing optical fiber of claim 20, wherein said fiber has a scattering-induced attenuation greater than 2000 dB/km at illumination wavelength.

28. The light diffusing optical fiber of claim 20, wherein said fiber core is silica or silica doped with Al, Ti, P, Ge, or a combination thereof.

29. The light diffusing optical fiber of claim 20, wherein said fiber core radius is less than 500 μ

m.

30. The light diffusing optical fiber of claim 20, wherein said fiber core has a core radius of 125-300 μ

m.

31. The light diffusing optical fiber of claim 20, wherein the fiber has a bend loss less than 3 dB/turn when fiber can be bent in an arc with a 5 mm radius.

32. The light diffusing optical fiber of claim 20 wherein said nanostructures are voids filled with SO₂.