Integrated optoelectronic coupling and connector

• US 5,535,296 A
• Filed: 09/28/1994
• Issued: 07/09/1996
• Est. Priority Date: 09/28/1994
• Status: Expired due to Fees

• Current Assignee: NGK Insulators Limited
• Original Assignee: Optobahn Corporation
• Inventors: Uchida, Toshi K.
• Primary Examiner(s): Lee, John D.
• Assistant Examiner(s): Palmer, Phan T. H.
• Application Number:
  US08/313,765
• Time in Patent Office: 650 Days
• Field of Search: 385/14.8, 385/15, 385/88-94, 385/125, 385/137
• US Class Current: 385/89
• CPC Class Codes: G02B 6/421 the intermediate optical component consisting of a short length of fibre, e.g. fibre stub
• CPC Class Codes: G02B 6/423 using guiding surfaces for the alignment
• CPC Class Codes: G02B 6/4231 with intermediate elements, e.g. rods and balls, between the elements
• CPC Class Codes: G02B 6/4232 using the surface tension of fluid solder to align the elements, e.g. solder bump techniques flip-chip mounting techniques in assembly of semiconductor devices H01L24/81
• CPC Class Codes: G02B 6/4238 Soldering
• CPC Class Codes: G02B 6/4249 comprising arrays of active devices and fibres
• CPC Class Codes: G02B 6/4292 the light guide being disconnectable from the opto-electronic element, e.g. mutually self aligning arrangements
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48465 the other connecting portion not on the bonding area being a wedge bond, i.e. ball-to-wedge, regular stitch
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2924/3025 Electromagnetic shielding

Abstract

An integrated mounting assembly has optical fibers supported between a grooved substrate and a clamping substrate, one or both substrates being mounted to a base substrate. The base substrate also provides integrated support for a submount which carries an optoelectronic device, e.g., a laser diode. Optical coupling of the device to the optical fibers is achieved by referencing the submount to the base without need for active optical alignment of the device. Mounting of the integrated optoelectronic assembly in a housing of an optoelectronic package can be made hermetic and electromagnetically shielded.

Claims

1. In a holder for a plurality of optical fibers of the type comprising a grooved substrate, a clamping substrate assembled to said grooved substrate for defining parallel channels therebetween, said channels being open at opposite sides of said grooved substrate, said optical fibers being clamped in said channels and terminating in fiber ends on one of said sides, and a lower substrate assembled to said grooved substrate to define therewith pin guides parallel to said channels, the improvement wherein said lower substrate is enlarged to define a base surface, a submount is affixed to said base surface and a laser diode is supported on said submount in substantial optical alignment with said fiber ends.

2. The improvement of claim 1 further comprising reference means for positioning said submount in relation to said base surface so as to achieve substantially precise optical alignment of said laser diode with said fiber ends whereby optical alignment is achieved by positioning said submount on said base without reference to said fiber ends.

3. The improvement of claim 2 wherein said reference means comprise first side means on said submount in register with second side means on said base surface.

4. The improvement of claim 2 wherein said reference means comprise guide pin inserted through said pin guides, said submount being positioned between said guide pins.

5. An integrated mounting assembly for coupling an optoelectronic device to optical fiber, comprising:

a plurality of optical fibers supported between a first substrate grooved to define fiber containing channels open on opposite sides of the grooved substrate and a second substrate assembled to said first substrate for clamping said optical fibers therebetween, a base substrate assembled to said first and said second substrates, said optical fibers in said channels terminating in fiber ends on one of said sides, said base substrate being enlarged to define a base surface, and a submount on said base surface supporting a laser diode in substantial optical alignment with said fiber ends;

reference means configured and adapted for positioning said submount with said laser diode thereon in substantially precise relationship to said base whereby substantially precise optical alignment of the laser diode with said fiber ends is achieved without referencing the laser diode to said fiber ends.

6. The integrated mounting of claim 5 wherein said submount has a metallized undersurface soldered to a metallized upper surface of said base.

7. The integrated mounting of claim 5 wherein said submount is entirely surface metallized, said laser diode has a common electrode soldered to said top surface, and said submount is soldered to a metallized surface of said base.

8. The integrated mounting of claims 5 further comprising at least two power supply electrodes on said upper surface, said laser diode being fixed to said top surface by one or more anode electrodes each soldered directly to a corresponding one of said supply electrodes, said diode having a common cathode electrode wire bonded to another of said supply electrodes.

9. The integrated mounting of claim 5 further comprising at least two power supply electrodes on said upper surface, said laser diode being fixed to said top surface by a common cathode electrode directly soldered to one of said supply electrodes, said diode having one or more anode electrodes each wire bonded to a corresponding one of said supply electrodes.

10. The integrated mounting of claim 5 further comprising optical scrambler means interposed between said laser diode and said fiber ends.

11. The integrated mounting of claim 10 wherein said scrambler means is made of said same material.

12. The integrated mounting of claim 11 wherein said scrambler means is affixed to one or both of said base and said substrate.

13. The integrated mounting of claim 5 wherein said optical fibers also terminate in fiber ends at the other of said opposite sides, and further comprising means on one or both of said base and said substrate engageable by a connector attached to a fiber optic cable for coupling said optical fibers to the fiber optic cable.

14. The assembly of claim 5 wherein said reference means comprise edge means of said submount and said base in registry with each other.

15. The assembly of claim 14 further comprising electrically conductive traces deposited on said submount and soldered to corresponding electrical contacts on said laser diode, said conductive traces being dimensioned, configured and arranged for positioning said laser diode on said submount with sufficient precision for achieving a desired degree of said optical alignment.

16. The assembly of claim 5 wherein said first substrate, said second substrate said base and said submount are made of the same material, said material being characterized by a low coefficient of thermal expansion.

17. The assembly of claim 16 wherein said material is a ceramic.

18. The assembly of claim 16 wherein said material is alumina.

19. The assembly of claim 16 wherein said submount is a rectangular block.

20. A hermetically sealed optoelectronic package comprising:

an enclosure having a plurality of walls including one wall having a mounting hole;

an optoelectronic assembly mounted in said hole, an optical cable having one or more optical fibers terminating in fiber ends clamped between two or more substrates which together constitute an optical fiber holder, said cable extending from an outer side of said holder, one of said substrates also supporting an optoelectronic device optically coupled to said fiber ends on an inner side of said holder;

said holder being supported in said hole and joined in a hermetic seal to said one wall with said outer side of said holder exteriorly to said enclosure and said inner side of said holder interiorly to said enclosure.

21. The optoelectronic package of claim 20 comprising seal means between said holder and said one wall.

22. The optoelectronic package of claim 21 wherein said seal means is of electrically conductive material.

23. The optoelectronic package of claim 21 wherein said holder has metallized surfaces and said seal means are of electrically conductive material, whereby said hermetic seal also provides electromagnetic shielding.

24. The optoelectronic package of claim 20 wherein said fiber ends have a circular cross section and are contained in channels of triangular cross section defined between said substrates, void spaces defined in said channels between said triangular cross-section and said circular cross-section, filler material filling said void spaces for hermetically sealing said channels between said inner side and said outer side.

25. The optoelectronic package of claim 24 wherein said channels have interior wall surfaces and said optical fibers each have an outer fiber surface, said wall surfaces and said outer surface being metallized, said filler material comprising metallic solder.

26. A hermetically sealed optoelectronic package comprising:

an optoelectronic package housing having a plurality of walls including one wall having a mounting hole;

an optoelectronic assembly mounted in said hole, an optical cable having one or more optical fibers terminating in fiber ends clamped between two or more substrates which together constitute an optical fiber holder, said cable extending from an outer side of said holder, one of said substrates also supporting an optoelectronic device optically coupled to said fiber ends on an inner side of said holder, said holder having metallized surfaces and electrically conductive seal means between said metallized surfaces and said one wall making a hermetically sealed and electromagnetically shielded mounting of said optoelectronic assembly to said housing.

27. The optoelectronic package of claim 26 wherein said fiber ends are contained in channels defined between said substrates, voids extending the length of said channels between said fibers and said substrates, and filler material filling said voids to seal said channels.

28. The optoelectronic package of claim 27 wherein said filler material is electrically conductive to provide electromagnetic shielding of said housing.

29. A method for assembling a laser diode to an integrated mounting carrying optical fiber, comprising the steps of:

providing an integrated mounting having a base, a substrate on said base, a plurality of parallel channels defined between said base and substrate, said channels being open at opposite front and rear sides of said substrate, optical fibers in said channels terminating in fiber ends on said front side;

positioning a pair of parallel pins in pin guides defined in said base or said substrate on opposite sides of said fiber ends;

providing a submount having a top surface, a bottom and two opposite sides between said top surface and said bottom, the submount being dimensioned between said opposite sides so as to make a close sliding fit between said pins;

fixing a laser diode to said top surface;

positioning said submount with said bottom on said base, said opposite sides between said parallel pins and said laser diode in facing but spaced relation to said fiber;

permanently affixing said submount to said base; and

removing said parallel pins.

30. A method for assembling a laser diode array having a plurality of diode electrodes on one side and a common electrode on another side of the diode array to an integrated mounting carrying optical fiber, comprising the steps of:

providing an integrated mounting having a base, a substrate on said base, a plurality of parallel channels defined between said base and substrate, said channels being open at opposite front and rear sides of said substrate, optical fibers in said channels terminating in fiber ends on said front side;

providing a submount having a top surface including a front edge and a plurality of supply electrodes on said top surface;

positioning said diode array in register with said front edge and with said diode electrodes superposed on said supply electrodes, heating said electrodes to melt solder provided therebetween and allowing said diode array to be brought into precise register with said supply electrodes by surface tension of the molten solder, and cooling said solder to a solid state thereby to fix said diode array at a precise position along said front edge on said substrate; and

affixing said submount to said base with said diode array facing said fiber ends.

31. The method of claim 30 wherein said submount has a pair of opposite sides and said step of affixing said submount comprises:

positioning a pair of parallel pins in pin guides defined in said base or said substrate on opposite sides of said fiber ends, said pins being spaced apart by a distance equal to the dimension of the substrate between said opposite sides;

positioning said submount with said opposite sides in close sliding fit between said parallel pins and said laser diode in facing but spaced relation to said fiber;

permanently affixing said submount to said base; and

removing said parallel pins.