Universal coupling of small core optical fiber to large laser foci

• US 20070122084A1
• Filed: 11/30/2005
• Published: 05/31/2007
• Est. Priority Date: 11/30/2005
• Status: Active Grant

• Current Assignee: Thorlabs Incorporated
• Original Assignee: InnovaQuartz Inc. (Endo International PLC)
• Inventors: Stephen, Griffin
• Granted Patent: US 7,488,116 B2
• Time in Patent Office: Days
• US Class Current: 385/79
• 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
• CPC Class Codes: G02B 6/32 having lens focusing means positioned between opposed fibre ends with lens being an integral part of the single fibre end G02B6/262
• CPC Class Codes: G02B 6/322 and having centering means being part of the lens for the self-positioning of the lightguide at the focal point, e.g. holes, wells, indents, nibs
• CPC Class Codes: G02B 6/4204 the coupling comprising intermediate optical elements, e.g. lenses, holograms encapsulated active devices H01S5/02208, H01L33/52
• CPC Class Codes: G02B 6/4296 coupling with sources of high radiant energy, e.g. high power lasers, high temperature light sources

Abstract

It is often desirable to efficiently couple laser foci that are dimensionally large to dimensionally small optical fibers. A fiber fused in a lower refractive index fiber is disclosed. The fiber/ferrule construct is characterized by having no taper of the fiber in the ferrule and a negative lens shape at a fiber/ferrule face. This construct enable the coupling of imparting rays that fall outside of the fiber core into the transmission path of the fiber. Where the laser systems are integrated in a manner that precludes altering the focusing optic, such as in surgical laser systems, or where the laser'"'"'s beam focal properties are such that reducing the focal spot diameter is impractical for fiber coupling, modification of the optical fiber input geometry offers a means of customizing the laser-to-fiber interface for applications involving different fiber diameters.

Claims

1. An optical fiber termination comprising an optical fiber core and cladding fused within a transparent optical ferrule where the ferrule is of refractive index equal to or lower than the optical fiber cladding.

2. The fiber termination according to claim 1 further comprising a negative lens shape formed on the terminal end.

3. The fiber termination according to claim 1 where the fiber core is silica, the fiber cladding is doped silica and the ferrule is silica.

4. The fiber termination according to claim 2 where the fiber core is silica, the fiber cladding is doped silica and the ferrule is silica.

5. The fiber termination according to claim 3 where the fiber cladding dopant is fluorine.

6. The fiber termination according to claim 4 where the fiber cladding dopant is fluorine.

7. The fiber termination according to claim 1 where the fiber core is silica, the fiber cladding is doped silica and the ferrule is doped silica.

8. The fiber termination according to claim 2 where the fiber core is silica, the fiber cladding is doped silica and the ferrule is doped silica.

9. The fiber termination according to claim 7 where the fiber cladding dopant is fluorine and the ferrule dopant is fluorine.

10. The fiber termination according to claim 8 where the fiber cladding dopant is fluorine and the ferrule dopant is fluorine.

11. The fiber termination according to claim 7 where the ferrule dopant varies in concentration across the radius of the ferrule.

12. The fiber termination according to claim 8 where the ferrule dopant varies in concentration across the radius of the ferrule.

13. The fiber termination according to claim 1 where the fiber core is doped silica, the fiber cladding is silica and the ferrule is silica.

14. The fiber termination according to claim 2 where the fiber core is doped silica, the fiber cladding is silica and the ferrule is silica.

15. The fiber termination according to claim 13 where the fiber core dopant is germanium.

16. The fiber termination according to claim 14 where the fiber core dopant is germanium.

17. The fiber termination according to claim 1 where the fiber core is doped silica, the fiber cladding is silica and the ferrule is doped silica.

18. The fiber termination according to claim 2 where the fiber core is doped silica, the fiber cladding is silica and the ferrule is doped silica.

19. The fiber termination according to claim 17 where the fiber core dopant is germanium and the ferrule dopant is fluorine.

20. The fiber termination according to claim 18 where the fiber core dopant is germanium and the ferrule dopant is fluorine.

21. The fiber termination according to claim 17 where the ferrule dopant varies in concentration across the radius of the ferrule.

22. The fiber termination according to claim 18 where the ferrule dopant varies in concentration across the radius of the ferrule.

23. The fiber termination according to claim 1 where the fiber core is doped silica, the fiber cladding is doped silica and the ferrule is silica.

24. The fiber termination according to claim 2 where the fiber core is doped silica, the fiber cladding is doped silica and the ferrule is silica.

25. The fiber termination according to claim 23 where the fiber core dopant is germanium and the cladding dopant is fluorine.

26. The fiber termination according to claim 24 where the fiber core dopant is germanium and the cladding dopant is fluorine.

27. The fiber termination according to claim 1 where the fiber core is doped silica, the fiber cladding is doped silica and the ferrule is doped silica.

28. The fiber termination according to claim 2 where the fiber core is doped silica, the fiber cladding is doped silica and the ferrule is doped silica.

29. The fiber termination according to claim 27 where the fiber core dopant is germanium, the cladding dopant is fluorine and the ferrule dopant is fluorine.

30. The fiber termination according to claim 28 where the fiber core dopant is germanium, the cladding dopant is fluorine and the ferrule dopant is fluorine.

31. The fiber termination according to claim 27 where the ferrule dopant varies in concentration across the radius of the ferrule.

32. The fiber termination according to claim 28 where the ferrule dopant varies in concentration across the radius of the ferrule.

33. An optical fiber termination comprising an optical fiber core fused within a transparent optical ferrule where the ferrule is of refractive index equal to or lower than the optical fiber core.

34. The fiber termination according to claim 33 further comprising a negative lens shape formed on a terminal end, where the negative lens shape is a concave cavity having a diameter that is greater than or equal that of the fiber core.

35. The fiber termination according to claim 33 where the fiber core is silica and the ferrule is silica.

36. The fiber termination according to claim 34 where the fiber core is silica and the ferrule is silica.

37. The fiber termination according to claim 33 where the fiber core is silica and the ferrule is doped silica.

38. The fiber termination according to claim 34 where the fiber core is silica and the ferrule is doped silica.

39. The fiber termination according to claim 33 where the ferrule dopant is fluorine.

40. The fiber termination according to claim 34 where the ferrule dopant is fluorine.

41. The fiber termination according to claim 37 where the ferrule dopant varies in concentration across the radius of the ferrule.

42. The fiber termination according to claim 38 where the ferrule dopant varies in concentration across the radius of the ferrule.

43. A fiber termination comprising an optical fiber core fused within an optical ferrule where the fused ferrule has a refractive index equal to or lower than the fiber core and a negative lens shape is formed on a terminal end of the fiber termination.