ALIGNMENT FERRULE ASSEMBLIES AND CONNECTORS FOR EVANESCENT OPTICAL COUPLERS AND EVANESCENT OPTICAL COUPLERS USING SAME

• US 20200132934A1
• Filed: 10/31/2018
• Published: 04/30/2020
• Est. Priority Date: 10/31/2018
• Status: Active Grant

• Current Assignee: Corning Research & Development Corporation (Corning Incorporated)
• Original Assignee: Corning Research & Development Corporation (Corning Incorporated)
• Inventors: Sutherland, James Scott
• Granted Patent: US 10,895,687 B2
• Time in Patent Office: Days
• CPC Class Codes: G02B 6/30 for use between fibre and thin-film device
• CPC Class Codes: G02B 6/3616 Holders, macro size fixtures for mechanically holding or positioning fibres, e.g. on an optical bench supporting carriers of a microbench type G02B6/3648; micromanipulators B25J7/00; cassettes, bobbins G02B6/4439
• CPC Class Codes: G02B 6/3628 for mounting fibres to supporting carriers G02B6/3608, G02B6/3616 take precedence
• CPC Class Codes: G02B 6/3652 the additional structures being prepositioning mounting areas, allowing only movement in one dimension, e.g. grooves, trenches or vias in the microbench surface, i.e. self aligning supporting carriers
• CPC Class Codes: G02B 6/3684 characterised by the manufacturing process of surface profiling of the supporting carrier manufacturing microsystems per se B81C1/00015
• CPC Class Codes: G02B 6/3826 characterised by form or shape
• CPC Class Codes: G02B 6/3839 for a plurality of light guides
• CPC Class Codes: G02B 6/3861 Adhesive bonding adhesives in general C09J
• 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

Abstract

Disclosed is an optical interconnection device that includes an alignment ferrule assembly formed from an alignment substrate and optical fibers. The optical interconnection device also has an alignment assembly formed by a planar support member with guide features. A receiving region resides between the guide features in which the alignment substrate is secured. An evanescent optical coupler can be formed using the optical interconnection device as a first device and another optical interconnection device as a second device. The second device is constituted by a planar lightwave circuit that operably supports waveguides and an adapter. The adapter of the second device is configured to engage the alignment assembly of the first device to place the optical fibers and the optical waveguides of the respective devices in evanescent optical communication.

Claims

1. An optical interconnection device for establishing evanescent optical coupling between optical fibers and optical waveguides of a photonic lightwave circuit (PLC), comprising:

a) an alignment ferrule assembly comprising;

i) an alignment substrate having a front-end section with a front end, a top surface, a bottom surface and a substrate central axis;

ii) an array of optical fibers, with each optical fiber having a fiber central axis and an end section with a glass portion defined by glass core, a glass inner cladding and a glass-portion surface that resides immediately adjacent the glass core, and wherein the end sections of the optical fibers are secured to the bottom surface of the alignment substrate with the glass-portion surfaces facing away from the bottom surface of the alignment substrate and with the fiber central axes aligned with the substrate central axis; and

b) an alignment assembly comprising;

a planar support member having a back-end section with a back end, a top surface and a bottom surface;

first and second spaced-apart guide-feature support members that downwardly depend from the bottom surface of the planar support member and that respectively support first guide features; and

a receiving region between the first and second guide features in which the alignment substrate of the alignment ferrule assembly is secured.

2. The optical interconnection device according to claim 1, wherein the first and second spaced-apart guide-feature support members respectively comprise first and second guide tubes.

3. The optical interconnection device according to claim 1, wherein the first and second guide tubes respectively comprises first and second bores that respectively support a first guide pin and a second guide pin.

4. The optical interconnection device according to claim 1, wherein the first guide features are oriented at a connection angle φ

>

0 relative to the substrate central axis of the alignment substrate.

5. The optical interconnection device according to claim 1, further comprising a latch member supported at the back-end section of the planar support member.

6. The optical interconnection device according to claim 5, further comprising a spring-loaded carrier member having a bottom surface and disposed between the first and second spaced-apart guide-feature support members so that the top surface of the alignment substrate of the alignment ferrule assembly is removably attached to the bottom surface of the spring-loaded carrier member.

7. The optical interconnection device according to claim 5, wherein the alignment ferrule assembly comprises one or more spacer fibers interleaved with the optical fibers to define a pitch for the optical fibers that matches a pitch of the waveguides.

8. An evanescent optical coupler, comprising:

the optical interconnection device according to claim 1 as a first optical interconnection device;

a second optical interconnection device comprising;

a planar lightwave circuit (PLC) that operably supports PLC optical waveguides; and

an adapter operably supported by the PLC; and

wherein the adapter is configured to matingly engage the alignment assembly of the first optical interconnection device to place the optical fibers and the optical waveguides in evanescent optical communication.

9. The evanescent optical coupler according to claim 8, wherein the adapter comprises spaced-apart arms that respectively define second guide features configured to operably engage the first guide features of the alignment assembly.

10. The evanescent optical coupler according to claim 9, wherein the first and second guide features define a connection angle φ

>

0 relative to the substrate central axis of the alignment substrate.

11. The evanescent optical coupler according to claim 8, wherein the second optical interconnection device comprises a stop fixture having a recess configured to receive the front-end section of the alignment substrate of the alignment ferrule assembly when the first and second optical interconnection devices are matingly engaged.

12. The evanescent optical coupler according to claim 8, wherein the alignment ferrule assembly is attached to a spring-loaded carrier member, and wherein the adapter comprises a tongue that mechanically engages the carrier member and applies a pressing force that presses the alignment ferrule assembly against the PLC so that the optical fibers press against the optical waveguides when the first and second optical interconnection devices are matingly engaged.

13. The evanescent optical coupler according to claim 8, wherein the alignment ferrule assembly is attached to a spring-loaded carrier member, and wherein the housing assembly comprises at least one resilient member that mechanically engages the carrier member and applies a pressing force that presses the alignment ferrule assembly against the PLC so that the optical fibers press against the optical waveguides when the first and second optical interconnection devices are matingly engaged.

14. The evanescent optical coupler according to claim 8, wherein the at least one resilient member comprises a deflectable beam.

15. An optical interconnection device for establishing evanescent optical coupling between an array of optical waveguides and an array of optical fibers, comprising:

a planar lightwave circuit (PLC) having a surface and that supports the array of optical waveguides, wherein the array has first and second sides;

an adapter having an interior, spaced apart first and second tabs and spaced apart first and second arms each having a first guide feature, wherein the first and second tabs of the adapter are attached to the surface of the PLC adjacent and outboard of the first and second sides of the array of waveguides;

a stop fixture comprising a recess with an inside edge, the stop fixture attached to the surface of the PLC and within the interior of the adapter and relative to the optical waveguide array, with the recess defining an alignment surface.

16. The optical interconnection device according to claim 15, wherein the recess comprises a front-end section having a V-shape.

17. The optical interconnection device according to claim 15, wherein stop fixture has a planar top side and the inside edge makes an obtuse angle relative to the planar top side.

18. The optical interconnection device according to claim 15, wherein each first guide feature comprises a slot defined by upper and lower tines of each of the first and second arms.

19. The optical interconnection device according to claim 15, wherein the stop fixture comprises one or more resilient gripper elements.

20. An evanescent optical coupler, comprising:

the optical interconnection device according to claim 15 as a first optical interconnection device;

a second optical interconnection device comprising;

an alignment ferrule assembly comprising an alignment substrate having a substrate central axis and that supports an array of optical fibers;

an alignment assembly that operably supports the alignment ferrule assembly; and

wherein the adapter is configured to matingly engage with the alignment assembly of the second optical interconnection device to place the optical fibers and the optical waveguides in evanescent optical communication.

21. The evanescent optical coupler according to claim 20, wherein the alignment assembly comprises second guide features configured to operably engage with the first guide features of the alignment assembly.

22. The evanescent optical coupler according to claim 20, wherein the first and second guide features define a connection angle φ

>

0 relative to the substrate central axis of the alignment substrate.

23. The evanescent optical coupler according to claim 20, wherein the alignment substrate has a front-end section that is received within the recess of the stop fixture when the first and second optical interconnection devices are matingly engaged.

24. The evanescent optical coupler according to claim 23, wherein the alignment ferrule assembly is attached to a spring-loaded carrier member, and wherein the adapter comprises a tongue that mechanically engages the carrier member and applies a pressing force that presses the alignment ferrule assembly against the PLC so that the optical fibers press against the optical waveguides when the first and second optical interconnection devices are matingly engaged.

25. The evanescent optical coupler according to claim 24, wherein the stop fixture has a planar top side, and wherein the inside edge is angled other than perpendicular to the planar top side, and wherein the alignment substrate has an angled outside edge that allows either face-to-face contact or line contact between the outside edge of alignment substrate and the inside edge of the recess of the stop fixture.

26. The evanescent optical coupler according to claim 25, wherein the stop fixture comprises one or more resilient gripper elements configured to define an interference fit between the front-end section of the alignment substrate and the recess of the stop fixture.

27. The evanescent optical coupler according to claim 26, wherein the alignment ferrule assembly comprises a latch that is movable over first and second arms of the adapter to secure the alignment assembly to the adapter.

28. The evanescent optical coupler according to claim 23, wherein the alignment substrate has an outer edge that comprises one or more alignment bumps configured to align the optical fibers with the PLC waveguides for evanescent coupling when the one or more alignment bumps are in contact with the stop fixture.

29. A method of forming an alignment ferrule assembly, comprising:

drawing a glass preform to form a long glass member having a longitudinal axis, wherein the glass preform has at least one perform precision feature that defines at least one long glass member precision feature;

cutting the long glass member in a direction substantially perpendicular to the longitudinal axis to form an alignment substrate having at least one substrate precision feature defined by the at least one long glass sheet precision feature and further comprising a planar surface; and

securing a plurality of optical fibers to the planar surface.

30. The method according to claim 29, wherein the alignment substrate includes an edge and wherein at least one substrate precision feature is on the edge.

31. The method according to claim 29, wherein the at least one substrate alignment feature comprises a ridge that runs along the edge.

32. The method according claim 29, wherein the alignment substrate includes a V-shaped front end.

33. The method according to claim 29, wherein the planar surface includes a plurality of parallel V-grooves, and wherein each of the optical fibers is secured within one of the V-grooves.

34. The method according to claim 29, further comprising:

interfacing the optical fibers of the alignment ferrule assembly with optical waveguides supported by a planar lightwave circuit (PLC) substrate having a surface that supports a stop fixture, wherein the at least one substrate precision feature of the alignment substrate contacts the stop fixture when the optical fibers and the optical waveguides are operably aligned for evanescent coupling.

35. A method of forming an alignment ferrule assembly, comprising:

securing a plurality of optical fibers to a bottom surface of a planar alignment substrate so that the optical fibers run substantially parallel to the substrate axis and have a pitch P, wherein the planar alignment substrate has one or more edges; and

forming at least one alignment bump on at least one of the edges.

36. The method according to claim 35, wherein the forming of the at least one alignment bump comprises irradiating at least one of the edges with a laser beam.

37. The method according to claim 36, further comprising:

measuring a height of the at least one alignment bump; and

after said measuring, re-irradiating the at least one alignment bump to change the height of the at least one alignment bump.

38. The method according to claim 35, further comprising:

interfacing the optical fibers of the alignment ferrule assembly with optical waveguides having the pitch P and supported by a planar lightwave circuit (PLC) substrate having a surface that supports a stop fixture, wherein the at least one alignment bump of the alignment substrate contacts the stop fixture when the optical fibers and the waveguides are operably aligned.

39. The method according to claim 35, further comprising:

forming the alignment substrate by drawing a glass preform to form a long glass member and then cutting off a portion of the long glass member.

40. A method of forming a first optical interconnection device configured to receive a second optical interconnection device having an alignment ferrule assembly that supports an array of optical fibers having a pitch P, comprising:

providing a planar lightwave circuit (PLC) comprising a PLC substrate having a planar surface and that supports an array of PLC waveguides having the pitch P; and

securing a stop fixture to the planar surface and relative to the array of PLC waveguides so that the array of optical fibers and the array of PLC optical waveguides are operably aligned when the alignment ferrule assembly contacts the stop fixture.

41. The method according to claim 40, wherein securing the stop fixture to the planar surface comprises actively aligning first alignment marks on the stop fixture with second alignment marks on the PLC substrate.

42. The method according to claim 41, further comprising attached an adapter to the top surface of the PLC substrate, the adapter configured to receive and engage the second optical interconnection device.

43. The method according to claim 42, wherein the adapter comprises an open interior and wherein the stop fixture resides at least partially within the adapter interior.

44. The method according to claim 40, further comprising:

drawing a glass preform to form a long glass member having a recess and an inner edge, and then cutting off a portion the long glass member to define the stop fixture.

45. The method according to claim 44, wherein the alignment ferrule assembly comprises an alignment substrate having a V-shaped front-end section, and wherein the recess is V-shaped to closely accommodate the V-shaped front-end section of the alignment substrate.

46. The method according to claim 40, further comprising:

drawing a glass preform to form a long glass member;

cutting off at least first and second portions of the long glass member; and

defining the stop fixture using the at least first and second portions.

47. The method according to claim 40, wherein the stop fixture and the alignment ferrule assembly have complementary angled sidewalls, and wherein the complementary angled sidewalls make contact when the alignment ferrule assembly and the stop fixture come into contact.

48. The method according to claim 47, wherein the stop fixture comprises one or more resilient gripper elements.

49. The method according to claim 48, wherein the alignment ferrule assembly comprises an alignment substrate having a front-end section, and wherein the one or more resilient gripper elements define a recess sized to form an interference fit with the front-end section of the alignment substrate.

50. The method according to claim 40, wherein the alignment ferrule assembly comprises an alignment substrate having a front-end section with a front end comprising first and second beveled corners, and wherein the stop fixture comprises first and second posts having angled facets configured to receive to provide face-to-face contact with the beveled corners.

51. The method according to claim 40, wherein the alignment ferrule assembly comprises an alignment substrate having a front-end section with a front end comprising at least one recess, and wherein the stop fixture comprises at least one post sized to be received the at least one recess.

52. The method according to claim 40, wherein the alignment ferrule assembly comprises an alignment substrate having a front-end section with a front end, and wherein the stop fixture comprises a recess sized to receive the front-end section of the alignment substrate.

53. The method according to claim 40, wherein the alignment ferrule assembly comprises an alignment substrate having opposite edges each including a recess, and wherein the stop fixture comprises first and second resilient posts configured to respectively receive the first and second resilient posts.

54. The method according to claim 40, wherein the alignment ferrule assembly comprises an alignment substrate having at least one through hole, and wherein the stop fixture comprises at least one post configured to be received by the at least one through hole.