High density optical data storage

• US 20050013536A1
• Filed: 05/28/2004
• Published: 01/20/2005
• Est. Priority Date: 05/28/2003
• Status: Active Grant

• Current Assignee: Tufts University
• Original Assignee: Tufts University
• Inventors: Walt, David R.
• Granted Patent: US 6,999,657 B2
• Time in Patent Office: Days
• US Class Current: 385/27
• CPC Class Codes: G11B 7/1384 Fibre optics
• CPC Class Codes: G11B 7/1387 using the near-field effect
• CPC Class Codes: G11B 7/24 Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the arrangement of information on the carrier G11B7/007

Abstract

A data storage apparatus includes an array of optical fibers. The array has a first end and a second end. The first end of the array includes multiple optical fiber ends, each optical fiber end having an end face adapted for receiving light of a wavelength λ into the fiber for conveyance to the second end of the fiber array. The second end of the array includes multiple tapered optical fiber tips, each tapered optical fiber end having a minimum diameter less than λ. An opaque coating covers a portion of the tapered optical fiber tips. The data storage apparatus also includes a photochromic medium located within a distance λ of the second end of the array.

Claims

1. A data storage apparatus comprising:

(1) an array of optical fibers, the array having a first end and a second end, wherein

(a) the first end of the array comprises multiple optical fiber ends, each optical fiber end having an end face adapted for receiving light of a wavelength λ

into the fiber for conveyance to the second end of the fiber array; and

(b) the second end of the array comprises multiple tapered optical fiber tips, each tapered optical fiber end having a minimum diameter less than λ

;

(2) an opaque coating covering a portion of the tapered optical fiber tips; and

(3) a photochromic medium located within a distance λ

of the second end of the array.

2. The apparatus of claim 1, wherein a minimum diameter of the tapered optical fiber tips is between about 2 nm and about 1000 nm.

3. The apparatus of claim 1, wherein a minimum diameter of the tapered optical fiber tips is between about 2 nm and about 300 nm.

4. The apparatus of claim 1 wherein a minimum diameter of the tapered optical fiber tips is between about 2 nm and about 100 nm.

5. The apparatus of claim 1, wherein the opaque coating comprises a metal.

6. The apparatus of claim 5, wherein the metal is selected from the group consisting of gold, aluminum, silver, and chromium.

7. The apparatus of claim 1, wherein optical properties of the photochromic medium are changed when the medium is exposed to light of wavelength λ

.

8. The apparatus of claim 1, further comprising a light detector array positioned such that the photochromic medium is positioned between the light detector array and the array of optical fibers.

9. The apparatus of claim 8, wherein the light detector is a charge-coupled device.

10. The apparatus of claim 8, wherein the light detector comprises pixels.

11. The apparatus of claim 10, wherein each pixel of the light detector is associated with an optical fiber of the array.

12. The apparatus of claim 11, wherein each pixel has an area that is more than 1000 times greater than the area of an associated optical fiber'"'"'s tapered optical fiber end.

13. The apparatus of claim 1, further comprising an array of mirrors for directing light into the end faces of the optical fibers, each mirror being located at the first end of the array.

14. The apparatus of claim 9, wherein each mirror is positioned and adapted to direct light into a different optical fiber of the array.

15. The apparatus of claim 10, wherein the mirrors are movable between a first position for directing light into an optical fiber of the array and a second position for directing light away from the fibers of the array.

16. An apparatus for reading and writing data comprising:

(1) an array of optical fibers, the array having a first end and a second end, wherein

(a) the first end of the array comprises multiple optical fiber ends, each optical fiber end having an end face adapted for receiving light of a wavelength λ

into the fiber for conveyance to the second end of the fiber array; and

(b) the second end of the array comprises multiple tapered optical fiber tips, each tapered optical fiber end having a minimum diameter less than λ

;

(2) an opaque coating covering a portion of the tapered optical fiber tips;

(3) a photochromic medium located within a distance λ

of the second end of the array; and

(4) a laser for generating light of wavelength λ and

directing such light into the array of optical fibers.

17. The apparatus of claim 16, wherein a minimum diameter of the tapered optical fiber tips is between about 2 nm and about 300 nm.

18. The apparatus of claim 16, wherein a minimum diameter of the tapered optical fiber tips is between about 2 nm and about 100 nm.

19. The apparatus of claim 16, wherein the opaque coating comprises a metal.

20. The apparatus of claim 16, wherein optical properties of the photochromic medium are changed when the medium is exposed to light of wavelength λ

.

21. The apparatus of claim 16, further comprising a light detector array positioned such that the photochromic medium is positioned between the light detector array and the array of optical fibers.

22. The apparatus of claim 21, wherein the light detector is a charge-coupled device.

23. The apparatus of claim 21, wherein the light detector comprises pixels and each pixel of the light detector is associated with an optical fiber of the array.

24. The apparatus of claim 23, wherein each pixel has an area that is more than 1000 times greater than the area of an associated optical fiber'"'"'s tapered optical fiber end.

25. The apparatus of claim 16, further comprising an array of mirrors for directing light into the end faces of the optical fibers, each mirror being located at the first end of the array.

26. The apparatus of claim 25, wherein each mirror is positioned and adapted to direct light into a different optical fiber of the array.

27. The apparatus of claim 26, wherein the mirrors are movable between a first position for directing light into an optical fiber of the array and a second position for directing light away from the fibers of the array.

28. The apparatus of claim 16, further comprising a translation stage for translating the array from a first position relative to the medium to a second position relative to the medium.

29. A method of optically storing multiple data bits in parallel, the method comprising:

creating light having a wavelength λ

; and

directing light of wavelength λ

into first ends of selected individual optical fibers of an array of multiple co-axially arranged optical fiber, such that the light is conveyed to second ends of the optical fibers, from which the light exits and impinges on a photochromic medium whose optical properties can be altered by light of wavelength λ

, wherein the second tapered ends have a minimum diameter less than λ and

are positioned within a distance λ

of the photochromic medium.

30. The method of claim 29, further comprising:

positioning individual mirrors of an array of multiple mirrors, such that first selected individual mirrors direct the light into the first ends of the individual optical fibers and non-selected individual mirrors do not direct light into the first ends; and

shining light of wavelength λ

onto the array of multiple mirrors such that the light is reflected by the selected mirrors onto the first ends of individual optical fibers and is conveyed to the second ends of the optical fibers.

31. The method of claim 30, further comprising:

translating the array of optical fibers substantially parallel to a surface of the medium; and

again shining light of wavelength λ

onto the array of multiple mirrors such that the light is reflected by second selected mirrors onto the first ends of individual optical fibers and is conveyed to the second ends of the optical fibers, where the light exits the optical fibers and impinges on the photochromic medium.

32. A method of optically reading multiple data bits in parallel, the method of comprising:

directing light of a first wavelength λ

₁ into multiple first ends of individual optical fibers of an array of multiple co-axially arranged optical fibers, the individual optical fibers having second tapered ends with a minimum diameter less than λ

₁ and being positioned within a distance λ

₁ of a photochromic medium whose optical properties can be altered by light of a second wavelength λ

₂, wherein λ

₂ is not equal to λ

₁;

measuring an optical property of the photochromic medium representing a digital data bit at a location under each of the second tapered ends of the optical fibers; and

determining whether each data bit represents a “

1”

or a “

0”

based on the measurement of the optical properties.

33. The method of claim 32, wherein the optical property is a transmissivity of the medium.

34. The method of claim 32, further comprising:

translating the array of optical fibers substantially parallel to a surface of the medium;

again directing light of the first wavelength λ

₁ into the first ends of individual optical fibers of the array;

again measuring an optical property of the photochromic medium representing a digital data bit at a location under each of the second tapered ends of the optical fibers; and

again determining whether each data bit represents a “

1”

or a “

0”

based on the measurement of the optical properties.