Method and apparatus for measuring endface surface topography of multi-fiber fiberoptic connectors

• US 6,215,555 B1
• Filed: 01/07/1999
• Issued: 04/10/2001
• Est. Priority Date: 01/07/1999
• Status: Expired due to Term

• Current Assignee: Direct Optical Research Company
• Original Assignee: Direct Optical Research Company
• Inventors: Chivers, James T.
• Primary Examiner(s): Font, Frank G.
• Assistant Examiner(s): Lee, Andrew H.
• Application Number:
  US09/227,550
• Time in Patent Office: 824 Days
• Field of Search: 356/73.1, 356/345, 356/352, 356/357, 356/358, 356/450, 356/511, 356/513, 356/514
• US Class Current: 356/512
• CPC Class Codes: G02B 6/3833 Details of mounting fibres in ferrules; Assembly methods; Manufacture
• CPC Class Codes: G02B 6/3843 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 Class Codes: G02B 6/3882 using rods, pins or balls to align a pair of ferrule ends
• CPC Class Codes: G02B 6/3885 Multicore or multichannel optical connectors, i.e. one single ferrule containing more than one fibre, e.g. ribbon type optical ribbon cable G02B6/4403, G02B6/448
• CPC Class Codes: G02B 6/3898 Tools, e.g. handheld; Tuning wrenches; Jigs used with connectors, e.g. for extracting, removing or inserting in a panel, for engaging or coupling connectors, for assembling or disassembling components within the connector, for applying clips to hold two connectors together or for crimping tools for cleaning, G02B6/3866; tools in general B25B

Abstract

A system for evaluating a connector end surface of a multi-fiber fiberoptic connector having a precision guide pin hole for receiving a guide pin to precisely mate the connector with a like connector includes a reference guide pin having a polished flat reference surface oriented at a predetermined angle relative to a longitudinal axis of the reference guide pin. The reference guide pin is inserted into the guide pin hole. In one embodiment, an interferometer is first focused onto the connector end surface. The connector end surface is tipped and tilted to minimize or establish a viable fringe density on the connector end surface. The interferometer then acquires the interferogram data and produces an uncalibrated profile of the connector end surface. The interferometer then is focused on the reference surface and acquires its interferogram data, and then computes a profile of the reference surface. The profiles of the connector end surface and the reference surface are combined to provide a calibrated profile of the connector end surface. In another embodiment, the interferometer is focused on the reference guide pin first. The connector end surface then is tipped and tilted to establish a predetermined number of fringes thereon. The interferometer then profiles the connector end surface, which, because of the tipping and tilting, is calibrated relative to the guide pin hole.

Claims

1. A method of evaluating a connector end surface of a multi-fiber connector having a precision guide pin hole for receiving a guide pin to precisely mate the multi-fiber connector with a like multi-fiber connector, the method comprising:

(a) providing a reference guide pin having on one end thereof a polished reference surface oriented at a predetermined angle relative to a longitudinal axis of the reference guide pin;

(b) inserting the reference guide pin into the guide pin hole;

(c) focusing an interferometer on the reference surface to produce an interferogram of the reference surface;

(d) adjusting the relative orientation between the reference surface and a reference mirror of the interferometer as necessary to produce a predetermined fringe density of the interferogram of the reference surface;

(e) ensuring that the interferometer is focused on the connector end surface; and

(f) operating the interferometer to acquire data representative of an interferogram of the connector end surface and operating the interferometer to compute from the data a profile of the connector end surface, wherein the profile is precisely calibrated with reference to the guide pin hole, whereby the profile of the connector end surface is indicative of mateability of the multi-fiber connector with the like multi-fiber connector.

2. The method of claim 1, wherein step (b) includes using an insertion/removal tool to grip the reference guide pin and then insert the reference guide pin into the guide pin hole to a predetermined depth.

3. The method of claim 2, including using the insertion/removal tool to remove and hold the reference guide pin after step (f).

4. The method of claim 1, wherein the predetermined angle is a right angle.

5. The method of claim 1, wherein the predetermined angle is an acute angle.

6. The method of claim 5, wherein the acute angle is approximately 8 degrees.

7. The method of claim 5, wherein the acute angle is approximately equal to an angle of the connector end surface relative to the longitudinal axis of the reference guide pin when it is in the guide pin hole.

8. The method of claim 7, wherein step (b) includes rotationally orienting the reference guide pin about its longitudinal axis so that the reference surface is approximately parallel to the connector end surface.

9. The method of claim 1 wherein step (b) includes inserting the reference guide pin a predetermined depth into the guide pin hole.

10. The method of claim 1 wherein the predetermined fringe density is a minimum obtainable fringe density.

11. The method of claim 1 wherein the polished reference surface is flat.

12. The method of claim 1 including providing a zoom lens in the interferometer, and wherein step (f) includes determining if the interferogram of the connector end surface includes too many fringes, and if so, operating the zoom lens to provide a field of view of the connector end surface which includes only a reduced portion of the connector end surface and hence a reduced density of fringes, before computing the profile of the connector end surface.

13. The method of claim 1 wherein the ensuring of step (e) includes focusing the interferometer on the connector end surface if the connector end surface is not flush with the reference surface of the reference guide pin.

14. The method of claim 1 wherein the ensuring of step (e) includes maintaining the focus of the interferometer as established in step (c) if the reference surface of the reference guide pin is flush with the connector end surface.

15. A method of evaluating a connector end surface of a multi-fiber connector having a precision guide pin hole for receiving a guide pin to precisely mate the multi-fiber connector with a like multi-fiber connector, the method comprising:

(a) providing a reference guide pin having on one end thereof a polished reference surface oriented at a predetermined angle relative to a longitudinal axis of the reference guide pin;

(b) inserting the reference guide pin into the guide pin hole;

(c) focusing an interferometer on the connector end surface;

(d) adjusting the relative orientation between the connector end surface and a reference mirror of the interferometer as necessary to produce a predetermined fringe density of an interferogram of the connector end surface, and then operating the interferometer to acquire data from the interferogram of the connector end surface, and then operating the interferometer to produce from that data an uncalibrated profile of the connector end surface;

(e) ensuring that the interferometer is focused on the reference surface;

(f) operating the interferometer to acquire data representative of an interferogram on the reference surface, and operating the interferometer to compute from that data a profile of the reference surface; and

(g) operating the interferometer to utilize the profiles of the connector end surface and the reference surface to precisely calibrate the connector end surface relative to the guide pin hole to provide a calibrated profile of the connector end surface, whereby the calibrated profile of the connector end surface is indicative of mateability of the multi-fiber connector with the like multi-fiber connector.

16. The method of claim 15, wherein step (b) includes using an insertion/removal tool to grip the reference guide pin and then insert the reference guide pin into the guide pin hole to a predetermined depth.

17. The method of claim 16, including using the insertion/removal tool to remove and hold the reference guide pin after step (g).

18. The method of claim 15, wherein the predetermined angle is a right angle.

19. The method of claim 15, wherein the predetermined angle is an acute angle.

20. The method of claim 19, wherein the acute angle is approximately 8 degrees.

21. The method of claim 19, wherein the acute angle is approximately equal to an angle of the connector end surface relative to the longitudinal axis of the reference guide pin when it is in the guide pin hole.

22. The method of claim 21, where step (b) includes rotationally orienting the reference guide pin about its longitudinal axis so that the reference surface is approximately parallel to the connector end surface.

23. The method of claim 15 wherein step (b) includes inserting the reference guide pin a predetermined depth into the guide pin hole.

24. The method of claim 15 wherein the predetermined fringe density is a minimum obtainable fringe density.

25. The method of claim 15 wherein the polished reference surface is flat.

26. The method of claim 15 including providing a zoom lens in the interferometer, wherein step (f) includes determining if the interferogram of the reference surface includes too many fringes, and if so, operating the zoom lens to provide a field of view of the reference surface which includes only a reduced portion of the reference surface and hence a reduced density of fringes, before computing the profile of the reference surface.

27. A system for evaluating a connector end surface of a multi-fiber connector having a precision guide pin hole for receiving a guide pin to precisely mate the multi-fiber connector with a like multi-fiber connector, comprising:

(a) means for providing a reference guide pin having on one end thereof a polished reference surface oriented at a predetermined angle relative to a longitudinal axis of the reference guide pin;

(b) means for inserting the reference guide pin a predetermined depth into the guide pin hole;

(c) means for focusing an interferometer on the reference surface to produce an interferogram of the reference surface;

(d) means for adjusting the relative orientation between the reference surface and a reference mirror of the interfecrometer to produce a predetermined fringe density of the interferogram of the reference surface;

(e) means for focusing the interferometer on the connector end surface; and

(f) means for operating the interferometer to acquire data representative of an interferogram of the connector end surface and operating the interferometer to compute from the data a profile of the connector end surface, wherein the profile is precisely calibrated with reference to the guide pin hole, whereby the profile of the connector end surface is indicative of mateability of the multi-fiber connector with the like multi-fiber connector.

28. A system for evaluating a connector end surface of a multi-fiber connector having a precision guide pin hole for receiving a guide pin to precisely mate the multi-fiber connector with a like multi-fiber connector, comprising:

(a) means for providing a reference guide pin having on one end thereof a polished reference surface oriented at a predetermined angle relative to a longitudinal axis of the reference guide pin;

(b) means for inserting the reference guide pin into the guide pin hole;

(c) means for focusing an interferometer on the connector end surface;

(d) means for adjusting the relative orientation between the connector end surface and a reference mirror of the interferometer to produce a predetermined fringe density of an interferogram of the connector end surface, and then operating the interferometer to acquire data from the interferogram on the connector end surface, and then operating the interferometer to produce from that data an uncalibrated profile of the connector end surface;

(e) means for focusing the interferometer on the reference surface;

(f) means for operating the interferometer to acquire data representative of an interferogram of the reference surface, and operating the interferometer to compute from that data a profile of the reference surface; and

(g) means for operating the interferometer to utilize the profiles of the connector end surface and the reference surface to precisely calibrate the connector end surface relative to the guide pin hole to provide a calibrated profile of the connector end surface,

whereby the calibrated profile of the connector end surface is indicative of mateability of the multi-fiber connector with the like multi-fiber connector.

29. Apparatus for evaluating a connector end surface of a multi-fiber connector having a precision guide pin hole for receiving a guide pin to precisely mate the multi-fiber connector with a like multi-fiber connector, comprising:

(a) a reference guide pin having on one end thereof a polished reference surface oriented at a predetermined angle relative to a longitudinal axis of the reference guide pin;

(b) an insertion tool adapted to grip the reference guide pin and insert the reference guide pin a predetermined depth into the guide pin hole of the multi-fiber connector;

(c) an interferometer including an adjustment feature adapted to adjust the relative orientation between the reference surface and a reference mirror of the interferometer allow the interferometer to produce a predetermined fringe density of an interferogram of the reference surface, the interferometer also including a focusing feature adapted to focus the interferometer on the connector end surface to allow the interferometer to acquire data representative of an interferogram of the connector end surface and operating the interferometer to compute from the data a profile of the connector end surface, wherein the profile is precisely calibrated with reference to the guide pin hole, whereby the profile of the connector end surface is indicative of mateability of the multi-fiber connector with the like multi-fiber connector.

30. Apparatus for evaluating a connector end surface of a multi-fiber connector having a precision guide pin hole for receiving a guide pin to precisely mate the multi-fiber connector with a like multi-fiber connector, comprising:

(a) a reference guide pin having on one end thereof a polished reference surface oriented at a predetermined angle relative to a longitudinal axis of the reference guide pin;

(b) an insertion tool adapted to grip the reference guide pin and insert the reference guide pin a predetermined depth into the guide pin hole of the multi-fiber connector;

(c) an interferometer including an adjustment feature adapted to adjust the relative orientation between the connector end surface and a reference mirror of the interferometer to allow the interferometer to produce a predetermined fringe density of an interferogram of the connector end surface and then acquire data from the interferogram of the connector end surface and produce from that data an uncalibrated profile of the connector end surface, the interferometer including a focusing feature adapted to focus the interferometer on the reference surface to allow the interferometer to acquire data representative of an interferogram of the reference surface and compute from that data a profile of the reference surface, the interferometer including a computing feature adapted to utilize the profiles of the connector end surface and the reference surface to precisely calibrate the connector end surface relative to the guide pin hole to provide a calibrated profile of the connector end surface, whereby the calibrated profile of the connector end surface is indicative of mateability of the multi-fiber connector with the like multi-fiber connector.

31. A method of measuring a connector end surface of a multi-fiber connector having a precision guide pin mating feature for receiving a guide pin to precisely mate the multi-fiber connector with a like multi-fiber connector, the method comprising:

(a) providing a reference guide pin having on one end thereof a polished reference surface oriented at a predetermined angle relative to a longitudinal axis of the reference guide pin;

(b) inserting the reference guide pin a into the guide pin mating feature;

(c) focusing an interferometer on the reference surface to produce an interferogram of the reference surface;

(d) adjusting the relative orientation between the reference surface and a reference mirror of the interferometer as necessary to produce a predetermined fringe density of the interferogram of the reference surface;

(e) focusing the interferometer on the connector end surface; and

(f) operating the interferometer to acquire data representative of an interferogram of the connector end surface and operating the interferometer to compute from the data a profile of the connector end surface, wherein the profile is precisely calibrated with reference to the precision guide pin mating feature, whereby the profile of the connector end surface is indicative of mateability of the multi-fiber connector with the like multi-fiber connector.

32. The method of claim 31 wherein the predetermined angle is an acute angle, the method including rotationally orienting the reference guide pin about its longitudinal axis so that the reference surface is approximately parallel to the connector end surface.

33. A method of measuring a connector end surface of a multi-fiber connector having a precision guide pin mating feature for receiving a guide pin to precisely mate the multi-fiber connector with a like multi-fiber connector, the method comprising:

(a) providing a reference guide pin having on one end thereof a polished reference surface oriented at a predetermined angle relative to a longitudinal axis of the reference guide pin;

(b) inserting the reference guide pin a into the guide pin mating feature;

(c) focusing an interferometer on the connector end surface;

(d) adjusting the relative orientation between the connector end surface and a reference mirror of the interferometer to produce a predetermined fringe density of an interferogram of the connector end surface, and then operating the interferometer to acquire data from the interferogram of the connector end surface, and then operating the interferometer to produce from that data an uncalibrated profile of the connector end surface;

(e) ensuring that the interferometer is focused on the reference surface;

(f) operating the interferometer to acquire data representative of an interferogram of the reference surface, and operating the interferometer to compute from that data a profile of the reference surface; and

(g) operating the interferometer to utilize the profiles of the connector end surface and the reference surface to precisely calibrate the connector end surface relative to the guide pin mating feature to provide a calibrated profile of the connector end surface,

whereby the calibrated profile of the connector end surface is indicative of mateability of the multi-fiber connector with the like multi-fiber connector.

34. The method of claim 33 wherein the predetermined angle is an acute angle, the method including rotationally orienting the reference guide pin about its longitudinal axis so that the reference surface is approximately parallel to the connector end surface.

35. A method of evaluating a connector end surface of a multi-fiber connector having a precision guide pin hole for receiving a guide pin to precisely mate the multi-fiber connector with a like multi-fiber connector, the method comprising:

(a) providing a reference guide pin having on one end thereof a polished reference surface oriented at a predetermined angle relative to a longitudinal axis of the reference guide pin;

(b) inserting the reference guide pin a into the guide pin hole;

(c) focusing an interferometer on the reference surface to produce an interferogram of the reference surface;

(d) adjusting the relative orientation between the reference surface and a reference mirror of the interferometer as necessary to produce a predetermined fringe density of the interferogram of the reference surface;

(e) ensuring that the interferometer is focused on the connector end surface; and

(f) operating the interferometer to display an interferogram of the connector end surface, wherein the interferogram is precisely calibrated with reference to the guide pin hole.

36. A method of evaluating a connector end surface of a multi-fiber connector having a precision guide pin hole for receiving a guide pin to precisely mate the multi-fiber connector with a like multi-fiber connector, the method comprising:

(a) providing a reference guide pin having on one end thereof a polished reference surface oriented at a predetermined angle relative to a longitudinal axis of the reference guide pin;

(b) inserting the reference guide pin into the guide pin hole;

(c) focusing an interferometer on the connector end surface;

(d) adjusting the relative orientation between the connector end surface and a reference mirror of the interferometer if necessary to produce a viable fringe density of an interferogram of the connector end surface, and then operating the interferometer to acquire data from the interferogram of the connector end surface, and then operating the interferometer to produce from that data an uncalibrated profile of the connector end surface;

(e) ensuring that the interferometer is focused on the reference surface;

(f) operating the interferometer to acquire data representative of an interferogram of the reference surface if necessary, and operating the interferometer to compute from that data a profile of the reference surface; and

(g) operating the interferometer to utilize the profiles of the connector end surface and the reference surface to precisely calibrate the connector end surface relative to the guide pin hole to provide a calibrated profile of the connector end surface, whereby the calibrated profile of the connector end surface is indicative of mateability of the multi-fiber connector with the like multi-fiber connector.

37. The method of claim 36 wherein the ensuring of step (e) includes focusing the interferometer on the reference surface of the reference guide pin if the reference surface of the reference guide pin is not flush with the connector end surface.

38. The method of claim 36 wherein the ensuring of step (e) includes maintaining the focus of the interferometer as established in step (c) if the reference surface of the reference guide pin is flush with the connector end surface.