Polished fused optical fiber endface

• US 6,415,087 B1
• Filed: 11/10/1998
• Issued: 07/02/2002
• Est. Priority Date: 06/04/1997
• Status: Expired due to Fees

• Current Assignee: Corning Lasertron, Inc. (Corning Incorporated)
• Original Assignee: Corning Lasertron, Inc. (Corning Incorporated)
• Inventors: Hwu, Lee-Ching, Yang, Thomas Chaodung, Conover, Steven David
• Primary Examiner(s): Kim, Ellen E.
• Application Number:
  US09/189,644
• Time in Patent Office: 1,330 Days
• Field of Search: 385/123, 385/38, 385/78, 385/43, 385/33
• US Class Current: 385/123
• CPC Class Codes: B24B 19/226 of the ends of optical fibres
• CPC Class Codes: G02B 6/241 Light guide terminations
• 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
• CPC Class Codes: G02B 6/4203 Optical features
• CPC Class Codes: G02B 6/4237 Welding
• CPC Class Codes: H01S 5/147 having specially shaped fibre, e.g. lensed or tapered end portion

Abstract

An endface configuration of an optical fiber has a frustum region which is produced by polishing the endface. In order to produce the optimal rounded tip, however, the polished fiber is then fused. To increase coupling efficiency, the vertex angle of the polished frustum region is acute, preferably between 16 and 20°. Further, to create a hyperbolic endface surface, an intermediate frustum region is preferably polished prior to fusing tip. This fused tip is preferably has a circular cross-section.

Claims

1. A method for manufacturing a lens at an end of an optical fiber, the method comprising:

polishing the end while rotating the optical fiber around its axis to form a taper, the rotating including multiple offset axial rotations of the fiber against a polishing medium, the multiple offset axial rotations comprising;

contacting the end of the fiber with the polishing medium at a first axial position of the fiber;

angularly rotating the fiber about its lengthwise axis a first number of turns to polish the end of the fiber;

withdrawing the end of the fiber from contact with the polishing medium;

contacting the end of the fiber with the polishing medium at an axial position of the fiber offset from the first axial position; and

angularly rotating the end of the fiber about its lengthwise axis to polish the end of the fiber; and

fusing a tip.

2. A method as in claim 1, wherein the step of polishing the end of the fiber comprises checking the polished regions of the end of the fiber for levels of concentricity.

3. A method as in claim 2, further comprising controlling subsequent polishing based upon the detected levels concentricity.

4. A method as in claim 2, further comprising controlling subsequent polishing based upon the detected levels circular concentricity to re-center the endface.

5. A method as in claim 1, wherein the step of polishing the end of the fiber comprises controlling the angle between the fiber and a polishing wheel such that a vertex angle of the fiber is between 16°

and 50°

.

6. A method as in claim 1, wherein the step of polishing the end of the fiber comprises forming a lower polished region and an upper polished region such that a vertex angle of the lower polished region is smaller than the upper polished region.

7. A method as claimed in claim 1, wherein a vertex angle of a lower polished region is between 16°

and 20° and

a vertex angle of an upper polished region is between 44° and

50°

.

8. A method as in claim 1, wherein the step of polishing the end of the fiber comprises:

rough polishing in which the fiber tip is placed in contact with a polishing wheel while being rotated greater than 180°

around its axis; and

fine polishing in which the fiber tip is placed in contact with a polishing wheel while being rotated less than 180°

around its axis.

9. A method as in claim 1, wherein the step of polishing the end of the fiber comprises:

rough polishing in which the fiber tip is placed in contact with a polishing wheel while being rotated around its axis to form a lower polished region; and

a subsequent

finish polishing in which the fiber tip is placed in contact with a polishing wheel while being rotated around its axis on a finer grit polishing surface.

10. A method as in claim 1, wherein the polishing medium is a rotating polishing wheel.

11. A method as in claim 10, wherein the polishing wheel has multiple grits supporting different grades of polishing.

12. A method as in claim 1 further comprising the steps of:

illuminating the non-polished end of the fiber; and

viewing the polished endface to determine a lens shape at the fused tip.

13. A method for manufacturing a lens at an end of an optical fiber, the method comprising:

polishing the end while rotating the optical fiber around its axis to form at least two frustum regions; and

then

fusing a tip at the end of the optical fiber.

14. A method as claimed in claim 13, wherein the step of polishing the end of the fiber comprises checking the polished regions of the end of the fiber for levels of concentricity.

15. A method as claimed in claim 14 further comprising:

controlling a subsequent polishing of the end of the fiber based upon the detected levels of concentricity.

16. A method as claimed in claim 14 further comprising:

controlling a subsequent polishing of the end of the fiber based upon the detected levels circular concentricity to re-center the endface.

17. A method as claimed in claim 13, wherein the step of polishing the end of the fiber comprises controlling the angle between the fiber and a polishing wheel such that a vertex angle of the fiber is between 16°

and 50°

.

18. A method as claimed in claim 13, wherein the step of polishing the end of the fiber comprises forming a first polished frustum region and a second polished frustum region such that a vertex angle of the first polished frustum region is smaller than the second polished frustum region.

19. A method as claimed in claim 18, wherein the vertex angle of the first polished frustum region is between 16°

and 20° and

the vertex angle of the second polished frustum region is between 44° and

50°

.

20. A method as claimed in claim 13, wherein the step of polishing the end of the fiber comprises:

rough polishing in which the fiber tip is placed in contact with a polishing wheel while being rotated greater than 180°

around its axis; and

fine polishing in which the fiber tip is placed in contact with a polishing wheel while being rotated less than 180°

around its axis.

21. A method as claimed in claim 13, wherein the step of polishing the end of the fiber comprises:

rough polishing in which the fiber tip is placed in contact with a polishing wheel while being rotated around its axis to form a lower polished region; and

finish polishing in which the fiber tip is placed in contact with a polishing wheel while being rotated around its axis on a finer grit polishing surface.

22. A method of shaping an end of an optical fiber, the method comprising:

aligning an axial end of the optical fiber with respect to a polishing medium;

polishing the end of the optical fiber using at least two different grits on a surface of the polishing medium, the polishing medium rotating about an axis and having a first grit nearer its center of rotation different than a second grit further away from its center of rotation.

23. A method as in claim 22, wherein the polishing medium is a rotating polishing wheel.

24. A method as in claim 23, wherein the end of the optical fiber is axially rotated to produce a taper.

25. A method as in claim 24, wherein an angle of a taper at the end of the fiber is between about 16°

and 20°

.

26. A method as in claim 23, wherein a taper is produced at the end of the fiber by multiple offset axial rotations of the fiber against the polishing medium.

27. A method as in claim 23 further comprising:

polishing the end of the fiber by axially rotating the fiber against the polishing medium.

28. A method as in claim 27, wherein the fiber is polished at a first selected radial distance from a center of the polishing wheel and a successive step of polishing the end of the fiber is performed at a second selected radial distance from the center of the polishing wheel.

29. A method as in claim 28, wherein the fiber is axially rotated and offset from one step of polishing the fiber to another.

30. A method as in claim 27, wherein the fiber is axially rotated and offset from one step of polishing the fiber to another.

31. A method as in claim 22, wherein the polishing medium rotates about an axis and has a finer grit surface near its center of rotation than away from its center of rotation.

32. A method as in claim 31, wherein the surface of the polishing medium is flat.

33. A method for manufacturing a lens at an end of an optical fiber, the method comprising:

polishing the end of the fiber while rotating the optical fiber around its axis to form a lower polished region and an upper polished region such that a vertex angle of the lower polished region is smaller than a vertex angle of the upper polished region; and

fusing a tip.

34. A method for manufacturing a lens at an end of an optical fiber, the method comprising:

polishing the end of the fiber while rotating the optical fiber around its axis so that a vertex angle of a lower polished region is between 16° and

20° and

a vertex angle of an upper polished region is between 44° and

50°

; and

fusing a tip.