Methods of ferrule reshaping for correcting core-to-ferrule concentricity errors, and optical fiber cable assemblies related to such methods

Patent metadata

Field	Value
Publication number	US-10336644-B2
Application number	US-201715602468-A
Country	US
Kind code	B2
Filing date	May 23, 2017
Priority date	May 26, 2016
Publication date	Jul 2, 2019
Grant date	Jul 2, 2019

Abstract

Methods of reshaping ferrules (20) used in optical fiber cables assemblies (170) are disclosed. The reshaping methods reduce a core-to-ferrule concentricity error (E), which improves coupling efficiency and optical transmission. The methods include measuring a distance (δ) and angular direction (θ) from a true center (30) of the ferrule to the core (46), wherein the true center (30) is based on an outer surface (26) of the ferrule. The methods also include reshaping at least a portion (26P) of the ferrule (20) to define a new true center (30′) of the ferrule (20) and reduce the distance (δ). A variety of reshaping techniques are also disclosed.

First claim

What is claimed is:

1. A method for reducing a core-to-ferrule concentricity error for a ferrule having an axial bore sized to operably support an optical fiber having a core, the method comprising:
measuring a distance δ from a true center of the ferrule to the core, wherein the true center is based on an outer surface of the ferrule; and
reshaping at least a portion of the ferrule to redefine the true center of the ferrule and reduce the distance δ, wherein the reshaping includes enlarging a portion of the ferrule.

2. The method according to claim 1 , wherein the ferrule has a maximum outer diameter with a diameter tolerance before the step of reshaping, and further wherein the step of reshaping maintains the maximum outer diameter of the ferrule within the diameter tolerance.

3. The method according to claim 1 , wherein reducing the distance δ results in a decrease in an optical insertion loss of at least 0.01 dB.

4. The method according to claim 1 , wherein the ferrule includes a central axis that extends through the true center, wherein the step of measuring further comprises measuring an angular direction θ from the true center of the ferrule to the core, and wherein the angular direction θ is measured relative to a reference line passing through the true center in a plane perpendicular to the central axis of the ferrule.

5. The method according to claim 1 , wherein the ferrule is substantially cylindrical and has a cross-sectional shape with a circularity tolerance, and further wherein the step of reshaping maintains the cross-sectional shape within the circularity tolerance.

6. The method according to claim 5 , wherein the circularity tolerance is 0.5 microns (μm) or less.

7. The method according to claim 5 , wherein the circularity tolerance of the ferrule is 0.04% of a nominal diameter of the ferrule.

8. The method according to claim 1 , wherein the step of reshaping includes generating at least one deformation on the outer surface of the ferrule.

9. The method according to claim 8 , wherein the at least one deformation deviates from a nominal diameter of the ferrule by a distance D d measured along a reference line extending through the true center, the distance D d being at least 0.04% of the nominal diameter.

10. The method according to claim 1 , wherein the step of reshaping includes removing material from the ferrule.

11. The method according to claim 10 , wherein the step of removing material from the ferrule includes any one or more of the following: grinding, polishing, and laser ablation.

12. The method according to claim 1 , wherein the step of enlarging a portion of the ferrule includes causing material of the ferrule to locally expand to form one or more protuberances on the outer surface of the ferrule.

13. The method according to claim 12 , wherein the step of reshaping includes irradiating one or more locations on the outer surface of the ferrule with a laser beam.

14. The method according to claim 12 , further comprising after the formation of the one or more protuberances:
reducing the size of at least one of the one or more protuberances.

15. The method according to claim 1 , further including forming an optical fiber connector with the ferrule after the step of reshaping.

16. A method of reducing a core-to-ferrule concentricity error in a ferrule having a central axis, an outer surface, and an axial bore sized to operably support a bare fiber section of an optical fiber having a core, the method comprising:
determining a true center of the ferrule based on the outer surface of the ferrule, wherein the central axis of the ferrule extends through the true center;
establishing the core-to-ferrule concentricity error by determining a distance δ from the true center of the ferrule to the core and determining an angular direction θ from the true center to the core, wherein the angular direction θ is measured relative to a reference line passing through the true center in a plane perpendicular to the central axis of the ferrule; and
reshaping at least a portion of the outer surface of the ferrule to reduce the distance δ, wherein a circularity error of the ferrule increases as a result of the reshaping.

17. The method according to claim 16 , wherein the step of reshaping includes forming at least one deformation on an outer surface of the ferrule.

18. The method according to claim 17 , wherein the at least one deformation deviates from a nominal diameter of the ferrule by a distance D d measured along a reference line extending through the true center, the distance D d being at least 0.04% of the nominal diameter.

19. The method according to claim 16 , wherein the step of reshaping includes removing material from the ferrule.

20. The method according to claim 19 , wherein the step of removing material from the ferrule includes any one or more of the following: grinding, polishing, and laser ablation.

21. The method according to claim 16 , wherein the step of reshaping includes enlarging a portion of the ferrule.

22. The method according to claim 21 , wherein the step of enlarging a portion of the ferrule includes causing material of the ferrule to locally expand to form one or more protuberances in the outer surface.

23. The method according to claim 21 , wherein the step of reshaping includes irradiating one or more locations on the outer surface of the ferrule with a laser beam.

24. The method according to claim 16 , further including forming an optical fiber connector using the ferrule after the step of reshaping.

Assignees

• Corning Optical Communications LLC
• Corning Optical Communication Llc

Inventors

• Bookbinder Dana Craig
• Piech Garrett Andrew
• Sutherland James Scott
• Webb Michael Brian
• Zambrano Elvis Alberto

Classifications

• G02B6/3887

  Anchoring optical cables to connector housings, e.g. strain relief features · CPC title

• G02B6/3821

  with axial spring biasing or loading means (G02B6/3847 takes precedence) · CPC title

• G02B6/3825

  with an intermediate part, e.g. adapter, receptacle, linking two plugs · CPC title

• C03B2201/40

  doped with transition metals other than rare earth metals, e.g. Zr, Nb, Ta or Zn · CPC title

• G02B6/3843

  with auxiliary facilities for movably aligning or adjusting the fibre within its ferrule, e.g. measuring position or eccentricity (testing the alignment of axes, including eccentricity, G01B11/27) · CPC title