Double hermetic package for fiber optic cross connect

• US 6,374,007 B1
• Filed: 04/14/2000
• Issued: 04/16/2002
• Est. Priority Date: 04/14/2000
• Status: Expired due to Fees

• Current Assignee: C Speed, LLC
• Original Assignee: C Speed, LLC
• Inventors: Hagelin, Paul Merritt, Bhattarai, Amal Ranjan
• Primary Examiner(s): Schuberg, Darren
• Assistant Examiner(s): ASSAF, FAYEZ G
• Application Number:
  US09/549,798
• Time in Patent Office: 732 Days
• Field of Search: 385/17, 385/18, 385/19, 359/233, 359/224, 359/872, 359/873
• US Class Current: 385/17
• CPC Class Codes: G02B 6/3512 the optical element being reflective, e.g. mirror
• CPC Class Codes: G02B 6/3556 NxM switch, i.e. regular arrays of switches elements of matrix type constellation
• CPC Class Codes: G02B 6/356 in an optical cross-connect device, e.g. routing and switching aspects of interconnecting different paths propagating different wavelengths to (re)configure the various input and output links switching polarized beams G02B6/3594; power equalizers G02B6/356 and G02B6/3594; path selecting means H04Q11/0001
• CPC Class Codes: G02B 6/3582 Housing means or package or arranging details of the switching elements, e.g. for thermal isolation
• CPC Class Codes: G02B 6/43 Arrangements comprising a plurality of opto-electronic elements and associated optical interconnections
• CPC Class Codes: H04Q 11/0005 Switch and router aspects
• CPC Class Codes: H04Q 2011/0024 using space switching
• CPC Class Codes: H04Q 2011/0026 using free space propagation (e.g. lenses, mirrors)
• CPC Class Codes: H04Q 2011/0041 Optical control
• CPC Class Codes: Y10S 359/904 Micromirror

Abstract

The present invention provides a double fiber optic cross connect (OXC) package. The double package includes a substrate with a first surface and a second surface; a micromirror array coupled to the second surface of the substrate; a first cap optically coupled to the micromirror array; and a second cap optically coupled to the micromirror array. The first cap, along with a substrate populated with a micromirror array and a set of sidewalls, form a volume which is preferably hermetically sealed. This volume is further packaged by the second cap with another set of sidewalls. With the first cap, only a short distance is used in redirecting the light. This short distance is uniform for each micromirror in the switch. The major portion of the beam is thus available for scanning. With the second cap, the light beam is folded during the switching operation, resulting in a smaller switch package. By folding the light in the switch architecture, the size of the switch package is reduced. Using the substrate in combination with a modular approach to substrate population allows for a single substrate switch with a higher device yield and scalability. Integrated circuits may be placed on the same substrate as the micromirrors, and the complexity of the assembly process is reduced.

Claims

1. A fiber optic cross connect (OXC), comprising:

a substrate with a first surface and a second surface;

a micromirror array coupled to the second surface of the substrate;

a first cap optically coupled to the micromirror array; and

a second cap optically coupled to the micromirror array.

2. The OXC of claim 1, wherein the second cap is more distally optically coupled to the micromirror array than the first cap.

3. The OXC of claim 1, wherein the second surface of the substrate is parallel to the first surface of the substrate.

4. The OXC of claim 1, wherein the substrate comprises a slab, wherein the slab is transparent to wavelengths of interest.

5. The OXC of claim 1, wherein the substrate comprises holes through which the light beams may travel.

6. The OXC of claim 1, wherein the substrate comprises a double-sided polished silicon wafer.

7. The OXC of claim 1, wherein the substrate comprises:

a first anti-reflective coating on the first surface of the substrate; and

a second anti-reflective coating on the second surface of the substrate.

8. The OXC of claim 1, wherein the substrate comprises:

integrated circuits on the first or the second surfaces of the substrate; and

conductive traces on the first or the second surfaces of the substrate.

9. The OXC of claim 8, wherein the integrated circuits are in close proximity to the micromirror array.

10. The OXC of claim 8, wherein the integrated circuits and conductive traces are absent from paths of light beams traveling through the substrate.

11. The OXC of claim 1, further comprising a plurality of photodetectors coupled to the substrate at a location where light beams travel in or out of the substrate.

12. The OXC of claim 1, wherein the micromirror array comprises a plurality of static mirrors.

13. The OXC of claim 1, wherein the micromirror array comprises a plurality of active mirrors.

14. The OXC of claim 1, wherein the micromirror array comprises a plurality of strips, wherein each of the plurality of strips comprises a plurality of micromirrors of the micromirror array.

15. The OXC of claim 1, wherein the micromirror array comprises a plurality of input micromirrors and a plurality of output micromirrors.

16. The OXC of claim 1, wherein the micromirror array is a two dimensional array.

17. The OXC of claim 1, wherein the first cap is parallel to the first and second surfaces of the substrate.

18. The OXC of claim 17, further comprising a first set of sidewalls coupled to the first cap and the second surface of the substrate.

19. The OXC of claim 17, wherein the first cap further comprises:

a plurality of reflecting surfaces, wherein the plurality of reflecting surfaces reflects light beams between a plurality of collimators and the micromirror array.

20. The OXC of claim 19, wherein a distance traveled by the light beams between the plurality of collimators and the micromirror array is identical for each micromirror in the micromirror array.

21. The OXC of claim 19, wherein the plurality of reflecting surfaces is coupled to a first surface of the first cap.

22. The OXC of claim 21, further comprising:

a plurality of photodetectors residing on a second surface of the first cap, wherein the first surface of the first cap is approximately parallel to the second surface of the first cap.

23. The OXC of claim 19, wherein the plurality of reflecting surfaces comprises a plurality of flat mirrors.

24. The OXC of claim 19, wherein the plurality of reflecting surfaces comprises a plurality of curved mirrors.

25. The OXC of claim 1, wherein the second cap folds light beams during a switching operation.

26. The OXC of claim 1, wherein a first surface of the second cap is parallel to a second surface of the first cap.

27. The OXC of claim 26, further comprising a second set of sidewalls coupled to the second cap and the second surface of the substrate.

28. The OXC of claim 26, further comprising a second set of sidewalls coupled to the second cap and the first cap.

29. The OXC of claim 1, further comprising a housing, wherein the housing comprises:

a plurality of optical fibers.

30. The OXC of claim 28, further comprising

a plurality of collimators optically coupled to the plurality of optical fibers, wherein the plurality of collimators is optically coupled to the first surface of the substrate.

31. The OXC of claim 1, further comprising a third cap, wherein a first surface of the third cap is optically coupled to a second surface of the second cap.

32. The OXC of claim 31, further comprising a third set of sidewalls coupled to the third cap and the second cap.

33. The OXC of claim 31, wherein a distance between the third cap and the second cap is approximately equal to a distance between the micromirror array and the second cap.

34. The OXC of claim 31, further comprising a plurality of photodetectors coupled to a second surface of the third cap.

35. An OXC, comprising:

a plurality of collimators;

a substrate with a first surface and a second surface, wherein the first surface of the substrate is optically coupled to the plurality of collimators;

a micromirror array coupled to the second surface of the substrate;

a first cap with a first surface and a second surface;

a plurality of reflecting surfaces coupled to the first surface of the first cap, wherein the plurality of reflecting surfaces reflects light beams between the plurality of collimators and the micromirror array;

a first set of sidewalls coupled to the first cap and the second surface of the substrate;

a second cap with a first surface and a second surface, wherein the first surface of the second cap is optically coupled to the micromirror array, wherein the second cap folds the light beams during a switching operation; and

a second set of sidewalls coupled to the second cap and the second surface of the substrate.

36. An OXC, comprising:

a plurality of collimators;

a substrate with a first surface and a second surface, wherein the first surface of the substrate is optically coupled to the plurality of collimators;

a micromirror array coupled to the second surface of the substrate;

a first cap with a first surface and a second surface;

a plurality of reflecting surfaces on the first surface of the first cap, wherein the plurality of reflecting surfaces reflects light beams between the plurality of collimators and the micromirror array;

a plurality of photodetectors coupled to the second surface of the first cap;

a first set of sidewalls coupled to the first cap and the second surface of the substrate;

a second cap with a first surface and a second surface, wherein the first surface of the second cap is optically coupled to the micromirror array, wherein the second cap folds the light beams during a switching operation; and

a second set of sidewalls coupled to the second cap and the second surface of the substrate.

37. An OXC, comprising:

a plurality of collimators;

a substrate with a first surface and a second surface, wherein the first surface of the substrate is optically coupled to the plurality of collimators;

a micromirror array coupled to the second surface of the substrate;

a first cap with a first surface and a second surface;

a plurality of reflecting surfaces on the first surface of the first cap, wherein the plurality of reflecting surfaces reflects light beams between the plurality of collimators and the micromirror array;

a first set of sidewalls coupled to the first cap and the second surface of the substrate;

a second cap with a first surface and a second surface, wherein the first surface of the second cap is optically coupled to the micromirror array, wherein the second cap folds the light beams during a switching operation;

a second set of sidewalls coupled to the second cap and the second surface of the substrate;

a third cap with a first surface and a second surface, wherein the first surface of the third cap is optically coupled to the second surface of the second cap;

a plurality of photodetectors coupled to the second surface of the third cap; and

a third set of sidewalls coupled to the third cap and the second cap.

38. An OXC, comprising:

a plurality of collimators;

a substrate with a first surface and a second surface, wherein the first surface of the substrate is optically coupled to the plurality of collimators;

a plurality of photodetectors coupled to the substrate at a location where light beams travel in or out of the substrate;

a micromirror array coupled to the second surface of the substrate;

a first cap with a first surface and a second surface;

a plurality of reflecting surfaces coupled to the first surface of the first cap, wherein the plurality of reflecting surfaces reflects light beams between the plurality of collimators and the micromirror array;

a first set of sidewalls coupled to the first cap and the second surface of the substrate;

a second cap with a first surface and a second surface, wherein the first surface of the second cap is optically coupled to the micromirror array, wherein the second cap folds the light beams during a switching operation; and

a second set of sidewalls coupled to the second cap and the second surface of the substrate.

39. A system, comprising:

a fiber optic transmission system; and

an OXC optically coupled to the fiber optic transmission system, the OXC comprising;

a substrate with a first surface and a second surface;

a microrrirror array coupled to the second surface of the substrate;

a first cap optically coupled to the micromirror array; and

a second cap optically coupled to the micromirror array.