Optical fiber with quantum dots

• US 20050111805A1
• Filed: 06/09/2004
• Published: 05/26/2005
• Est. Priority Date: 06/09/2003
• Status: Active Grant

• Current Assignee: Lambda Instruments Company, Virginia Tech Intellectual Properties, Inc.
• Original Assignee: Virginia Tech Intellectual Properties, Inc.
• Inventors: Hertz, Erik, Holton, Carvel, Paye, Corey, Meissner, Kenith
• Granted Patent: US 7,054,513 B2
• Time in Patent Office: Days
• US Class Current: 385/125
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: C03C 13/046 Multicomponent glass compositions
• CPC Class Codes: C03C 14/004 the non-glass component being in the form of particles or flakes
• CPC Class Codes: C03C 14/006 the non-glass component being in the form of microcrystallites, e.g. of optically or electrically active material
• CPC Class Codes: C03C 3/097 containing phosphorus, niobium or tantalum
• CPC Class Codes: C03C 3/102 containing lead
• CPC Class Codes: C03C 3/321 Chalcogenide glasses, e.g. containing S, Se, Te
• CPC Class Codes: C03C 4/0071 for laserable glass
• CPC Class Codes: C03C 4/12 for luminescent glass; for fluorescent glass
• CPC Class Codes: G02B 2006/0325 Fluid core or cladding
• 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 6/02357 Property of longitudinal structures or background material varies radially and/or azimuthally in the cladding, e.g. size, spacing, periodicity, shape, refractive index, graded index, quasiperiodic, quasicrystals
• CPC Class Codes: G02B 6/02366 Single ring of structures, e.g. "air clad"
• CPC Class Codes: G02B 6/02371 Cross section of longitudinal structures is non-circular
• CPC Class Codes: G02B 6/02385 Comprising liquid, e.g. fluid filled holes
• CPC Class Codes: G02B 6/032 with non solid core or cladding G02B6/02295 takes precedence
• CPC Class Codes: G02B 6/1225 comprising photonic band-gap structures or photonic lattices
• CPC Class Codes: H01S 3/06708 Constructional details of the fibre, e.g. compositions, cross-section, shape or tapering optical fibres as passive waveguides G02B6/02
• CPC Class Codes: H01S 3/06741 Photonic crystal fibre, i.e. the fibre having a photonic bandgap
• CPC Class Codes: H01S 3/169 : Nanoparticles, e.g. doped nanoparticles acting as a gain material

Abstract

Holey optical fibers (e.g. photonic fibers, random-hole fibers) are fabricated with quantum dots disposed in the holes. The quantum dots can provide light amplification and sensing functions, for example. When used for sensing, the dots will experience altered optical properties (e.g. altered fluorescence or absorption wavelength) in response to certain chemicals, biological elements, radiation, high energy particles, electrical or magnetic fields, or thermal/mechanical deformations. Since the dots are disposed in the holes, the dots interact with the evanescent field of core-confined light. Quantum dots can be damaged by high heat, and so typically cannot be embedded within conventional silica optical fibers. In the present invention, dots can be carried into the holes by a solvent at room temperature. The present invention also includes solid glass fibers made of low melting point materials (e.g. phosphate glass, lead oxide glass) with embedded quantum dots.

Claims

1. A holey optical fiber comprising:

a) a guiding region for carrying confined light;

b) a plurality of holes in the optical fiber, wherein light confined to the guiding region exists as an evanescent wave in the holes;

c) a plurality of quantum dots in the holes.

2. The holey optical fiber of claim 1 wherein the holey optical fiber is a photonic crystal-holey fiber or an index-guiding holey fiber.

3. The holey optical fiber of claim 1 wherein the holey optical fiber is a random-hole optical fiber.

4. The holey optical fiber of claim 1 wherein the holes are disposed in a cladding region of the optical fiber.

5. The holey optical fiber of claim 4 further comprising a solid core surrounded by the cladding region.

6. The holey optical fiber of claim 1 wherein the holes are disposed in a core region of the optical fiber.

7. The holey optical fiber of claim 1 further comprising a solvent disposed in the holes.

8. The holey optical fiber of claim 1 wherein the quantum dots are suspended in a solvent, colloid, gelatin or solid host.

9. The holey optical fiber of claim 1 wherein the quantum dots are supported by sidewalls of the holes.

10. The holey optical fiber of claim 1 further comprising a conventional solid fiber fusion spliced to the holey optical fiber so that the quantum dots are sealed within the holey optical fiber.

11. The holey optical fiber of claim 1 wherein the holes have a refractive index lower than the optical fiber material.

12. The holey optical fiber of claim 1 wherein the holes are sealed on at least one end so that the quantum dots are encapsulated within the fiber.

13. An optical fiber made of a glass having a drawing temperature less than 700 Celsius, and comprising quantum dots embedded within the glass.

14. The optical fiber of claim 13 wherein the quantum dots are embedded in the glass by an extrinsic doping processes.

15. The optical fiber of claim 13 wherein the fiber is made of a material selected from the group consisting of phosphate glass, lead glass and chalcogenide polymers.

16. The optical fiber of claim 13 wherein the glass comprises at least 35% by weight lead oxide.

17. The optical fiber of claim 13 wherein the drawing temperature is less than a boiling temperature of the quantum dot material.

18. The optical fiber of claim 13 wherein the glass has a drawing temperature less than 500 Celsius.

19. The optical fiber of claim 13 wherein the quantum dots are made of a material selected from the group consisting of tellurides and antimonides.

20. The optical fiber of claim 13 wherein the fiber comprises a core and a cladding, and wherein the quantum dots are disposed in the core.

21. The optical fiber of claim 13 wherein the fiber comprises a core and a cladding, and wherein the quantum dots are disposed in the cladding.

22. An optical fiber sensor, comprising:

a holey optical fiber comprising;

a) a guiding region for carrying confined light

b) a plurality of holes in the optical fiber;

c) a plurality of quantum dots in the holes; and

a light detector coupled to the holey optical fiber, operable for detecting a change in an optical characteristic of the quantum dots.

23. The optical fiber sensor of claim 22 wherein a change in electric or magnetic field causes a change in the optical characteristic of the quantum dots.

24. The optical fiber sensor of claim 22 wherein a change in exposure to cosmic particles, nuclear or other ionizing radiation causes a change in the optical characteristic of the quantum dots.

25. The optical fiber sensor of claim 22 wherein a change in chemical, biological or biochemical exposure causes a change in the optical characteristic of the quantum dots.

26. The optical fiber sensor of claim 22 wherein a change in mechanical properties in the fiber causes a change in the optical characteristic of the quantum dots.

27. The optical fiber sensor of claim 22 wherein at least some of the holes are open to the exterior of the fiber.

28. The optical fiber sensor of claim 22 further comprising a radiation source for injecting radiation into the fiber and wherein the quantum dots shift a wavelength of the radiation to longer wavelengths.