Optical assembly including fiber attachment

• US 5,179,609 A
• Filed: 08/30/1991
• Issued: 01/12/1993
• Est. Priority Date: 08/30/1991
• Status: Expired due to Term

• Current Assignee: American Telephone & Telegraph Company (AT&T, Inc.)
• Original Assignee: AT&T, Inc.
• Inventors: Dautartas, Mindaugas F., Blonder, Greg E., Wong, Yiu-Huen
• Primary Examiner(s): Ullah, Akm E.
• Application Number:
  US07/756,263
• Time in Patent Office: 501 Days
• Field of Search: 385/88-94
• US Class Current: 385/89
• CPC Class Codes: G02B 6/32 having lens focusing means positioned between opposed fibre ends with lens being an integral part of the single fibre end G02B6/262
• CPC Class Codes: G02B 6/4224 using visual alignment markings, e.g. index methods
• CPC Class Codes: G02B 6/4231 with intermediate elements, e.g. rods and balls, between the elements
• CPC Class Codes: G02B 6/4249 comprising arrays of active devices and fibres
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• 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

Abstract

An optical assembly is disclosed which utilizes a pair of separate members to support an optical device and an associated optical fiber. Fiducial features, in conjunction with an optical device conductive attachment means, are utilized to provide self-alignment between the device and the fiber. Aligned fiducials are formed on each member such that when the members are physically joined, alignment between the optical device and fiber is achieved. In particular, the members are mated such that a direct optical signal path between the device and fiber is formed.

Claims

1. An optical assembly comprising

a first member including top and bottom major surfaces for the mounting of at least one active optical device on said top major surface thereof, said first member comprising a first set of fiducial features formed on said top major surface and including electrically conductive bonding means for the attachment of said active optical device, said electrically conductive bonding means disposed on said top major surface at a predetermined location with respect to said first set of fiducial features;

and

a second member including top and bottom major surfaces for the support of at least one optical fiber, said second member including at least one longitudinal groove formed along said top major surface thereof for the placement of said at least one optical fiber, the second member further comprising a second set of fiducial features exposed in a surface orthogonal to said top major surface, said second set of fiducial features located so as to align with the location of the first set of fiducial features of said first member and provide fixed attachment of said first member to said second member.

2. An optical assembly as defined in claim 1 wherein the first member is capable of mounting a plurality of active optical devices and the second member is capable of supporting an associated plurality of optical fibers.

3. An optical assembly as defined in claim 1 wherein the first and second members comprise a semiconductor material.

4. An optical assembly as defined in claim 3 wherein the first and second members comprise silicon.

5. An optical assembly as defined in claim 1 wherein the first and second members comprise a plastic material .

6. An optical assembly as defined in claim 1 wherein the electrically conductive bonding means comprises a solder preform.

7. An optical assembly as defined in claim 6 wherein the solder preform is capable of being liquified when heated such that an optical device placed on the surface thereof will align to said preform upon heating.

8. An optical assembly as defined in claim 6 wherein the solder preform comprises a tin-gold combination.

9. An optical assembly as defined in claim 1 wherein the first and second fiducial features comprise a set of openings formed in the associated surfaces of the first and second members, respectively, the fiducial features further comprising a plurality of spherical members disposed between associated openings so as to provide mechanical mating of the first and second members.

10. An optical assembly as defined in claim 9 wherein the first and second members comprise silicon, wherein the fiducial openings comprise features etched into the silicon surface.

11. An optical assembly as defined in claim 1 wherein the first and second fiducial features comprise a set of grooves and ridges, a set of grooves formed on either one of the first and second member and the ridges formed on the remaining member, the grooves and ridges disposed to provide alignment between the first and second members upon mating.

12. An optical assembly as defined in claim 1 wherein the assembly further comprises

a third member disposed to cover the major surface of the second member supporting the optical fiber, the second and third members formed to include a plurality of fiducial features to facilitate the alignment and attachment therebetween.

13. An optical assembly as defined in claim 12 wherein the plurality of fiducial features comprises a first plurality of openings formed in the top major surface of the second member and an associated plurality of openings formed in the attaching surface of the third member, with a plurality of spherical members disposed therebetween.

14. An optical assembly as defined in claim 1 wherein the at least one active optical device comprises an LED.

15. An optical assembly as defined in claim 1 wherein the at least one active optical device comprises a photodiode.

16. An optical assembly as defined in claim 1 wherein the first member further includes a pair of electrical lead pads attached to the surface of the member to provide an electrical signal path to the active optical device.

17. An optical assembly as defined in claim 16 wherein the first member further includes electronic circuitry, disposed along the top surface thereof, associated with the operation of the active optical device.

18. A method of forming an optical assembly comprising the steps of:

a) providing first and second separate support members, each including a top major surface and sidewalls orthogonal thereto;

b) forming fiducial alignment features on the top major surface of said first support member and on a sidewall of said second support member;

c) forming electrically conductive bonding means on said top major surface of said first member at a predetermined location with respect to said associated fiducial alignment features;

d) forming a longitudinal groove along the top major surface of said second support member for the placement of an optical fiber, the longitudinal groove disposed to provide alignment between an active optical device and an optical fiber; and

e) fixing said first support member to said second support member by aligning and attaching the fiducial alignment features of said first member to the fiducial alignment features of said second member.

19. The method according to claim 18 wherein in performing step a), semiconductor substrate support members are provided.

20. The method according to claim 19 wherein the provided support members comprise silicon.

21. The method according to claim 20 wherein in performing steps b) and d), etching is used to form fiducial alignment features and the longitudinal groove.

22. The method according to claim 21 wherein in performing step e), spheres are inserted between and attached to the etched fiducial alignment features to achieve attachment of the first support member to the second support member.

23. The method according to claim 18 wherein in performing step a), plastic substrate support members are provided.

24. The method according to claim 18 wherein the method comprises the further steps of:

f) placing an active optical device on the conductive bonding means of step c); and

g) heating the conductive bonding means to liquify and allow said active optical device to align with the underlying conductive bonding means.