Portable digital holographic probe for the inspection of optical fiber connectors, and inspection system and method for the same

Patent metadata

Field	Value
Publication number	US-9733616-B2
Application number	US-201214368625-A
Country	US
Kind code	B2
Filing date	Dec 21, 2012
Priority date	Dec 28, 2011
Publication date	Aug 15, 2017
Grant date	Aug 15, 2017

Abstract

A portable inspection probe for the inspection of a recessed mating surface of an optical fiber connector is provided. In one variant, the portable inspection probe includes a digital holographic detection module operable to digitally record a hologram of the recessed mating surface, and a rigid probe tip configured to be optically coupled to the digital holographic detection module and shaped to provide optical access to the recessed mating surface. In another variant, the portable inspection probe is to be used with a rigid probe tip connectable thereto, and the digital holographic detection module includes a probing optical assembly not traversed by a reference beam and configured to direct an object beam onto the recessed mating surface and to collect the object beam upon reflection thereof by the recessed mating surface. An inspection system and an inspection method are also provided.

First claim

The invention claimed is:

1. A portable inspection probe for the inspection of a recessed mating surface of an optical fiber connector to be used with a rigid probe tip connectable thereto and shaped to provide optical access to the recessed mating surface, the portable inspection probe comprising:
a handheld portable housing comprising a tip connector to which the rigid probe tip is connectable, the rigid probe tip protruding from the handheld portable housing upon connection to the tip connector; and
a digital holographic detection module accommodated at least partly inside the handheld portable housing and configured to propagate an object beam and a reference beam along respective object and reference optical paths and to direct, without mechanical focus adjustment or control, the object and reference beams to interfere at a holographic detection plane after reflection of the object beam from the recessed mating surface, thereby forming the hologram of the recessed mating surface, the digital holographic detection module comprising:
a light source assembly configured to generate the object and reference beams;
a detector array positioned at the holographic detection plane and configured to digitally record the hologram of the recessed mating surface; and
a probing lens assembly configured to direct the object beam onto the recessed mating surface and to collect the object beam after reflection from the recessed mating surface.

2. The portable inspection probe according to claim 1 , wherein the probing lens assembly is not traversed by the reference.

3. The portable inspection probe according to claim 1 , wherein the object and reference beams meet at the holographic detection plane at a non-zero mutual angle.

4. The portable inspection probe according to claim 1 , wherein the light source assembly comprises a coherent light source configured to generate a coherent source beam and a beam splitter configured to split the coherent source beam into the object beam and the reference beam.

5. The portable inspection probe according to claim 4 , wherein the coherent light source is a laser source.

6. The portable inspection probe according to claim 1 , wherein the probing lens assembly comprises a triplet lens.

7. The portable inspection probe according to claim 1 , wherein the digital holographic detection module further comprises a beam combiner positioned in the object and reference optical paths, so as to combine and direct the reference and object beams to interfere at the holographic detection plane.

8. The portable inspection probe according to claim 7 , wherein the digital holographic detection module further comprises collimation optics configured to collimate the reference beam before interference with the object beam.

9. The portable inspection probe according to claim 8 , wherein the collimation optics comprises a triplet lens.

10. The portable inspection probe according to claim 1 , further comprising a processor configured to numerically synthesize at least one representation of the recessed mating surface of the optical fiber connector based on the hologram thereof.

11. The portable inspection probe according to claim 10 , wherein the processor is further configured to characterize at least one quality criterion from the numerically-synthesized at least one representation of the recessed mating surface.

12. The portable inspection probe according to claim 10 , wherein the processor is further configured to:
extract from the hologram of the recessed mating surface a complex wave field of the object beam at a holographic detection plane;
numerically propagate the complex wave field from the holographic detection plane to a synthesis plane; and
numerically synthesize the at least one representation of the recessed mating surface at the synthesis plane.

13. The portable inspection probe according to claim 12 , wherein the processor is further configured to numerically focus the complex wave field of the object beam at the synthesis plane by numerically propagating the complex wave field from the holographic detection plane to at least one test image plane, and selecting one of the at least one test image plane as the synthesis plane.

14. An inspection system comprising:
the portable inspection probe according to claim 1 ; and
a processor configured to:
receive the hologram of the recessed mating surface of the optical fiber connector digitally recorded by the digital holographic detection module of the portable inspection probe; and
numerically synthesize at least one representation of the recessed mating surface based on the hologram thereof.

15. The inspection system according to claim 14 , wherein the processor is further configured to characterize at least one quality criterion from the numerically-synthesized at least one representation of the recessed mating surface.

16. The inspection system according to claim 14 , wherein the processor is further configured to:
extract from the hologram of the recessed mating surface a complex wave field of the object beam at a holographic detection plane;
numerically propagate the complex wave field from the holographic detection plane to a synthesis plane; and
numerically synthesize the at least one representation of the recessed mating surface at the synthesis plane.

17. The inspection system according to claim 16 , wherein the processor is further configured to numerically focus the complex wave field of the object beam at the synthesis plane by numerically propagating the complex wave field from the holographic detection plane to at least one test image plane, and selecting one of the at least one test image plane as the synthesis plane.

18. The portable inspection probe according to claim 1 , further comprising said rigid probe tip configured to be optically coupled to the digital holographic detection module and shaped to provide optical access to the recessed mating surface.

19. A method for inspecting a recessed mating surface of an optical fiber connector with a portable inspection probe having a rigid probe tip connected thereto and shaped to provide optical access to the recessed mating surface, the recessed mating surface of the optical fiber connector being located in a recess, the method comprising the steps of:
a) inserting the rigid probe tip into the recess to provide optical access to the recessed mating surface while holding the handheld portable housing;
b) digitally obtaining a hologram of the recessed mating surface, comprising:
i) propagating an object beam and a reference beam along respective object and reference optical paths;
ii) along the object optical path, directing the object beam onto the recessed mating surface and collecting the same upon reflection thereof by the recessed mating surface using a probing optical assembly, wherein the probing optical assembly is not traversed by the reference beam;
iii) directing, without mechanical focus adjustment or control, the object and reference beams to interfere at a holographic detection plane, thereby forming the hologram of the recessed mating surface; and

c) numerically synthesizing at least one representation of the recessed mating surface of the optical fiber connector based on the hologram thereof.

20. The method according to claim 19 , wherein step c) comprises the substeps of:
i) extracting from the hologram of the recessed mating surface a complex wave field of the object beam at a holographic detection plane;
ii) numerically propagating the complex wave fiel

Assignees

• Exfo Inc

Inventors

• Ruchet Bernard
• Cyr Normand

Classifications

• G01N2201/0627

  Use of several LED's for spectral resolution · CPC title

• G03H1/0866 Primary

  Digital holographic imaging, i.e. synthesizing holobjects from holograms · CPC title

• G01M11/088

  of optical fibres; Mechanical features associated with the optical testing of optical fibres · CPC title

• G01N21/94

  Investigating contamination, e.g. dust (G01N21/85 takes precedence) · CPC title

• G02B21/0016 Primary

  Technical microscopes, e.g. for inspection or measuring in industrial production processes · CPC title