Fiber optic cross connect with uniform redirection length and folding of light beams

• US 6,347,167 B1
• Filed: 04/14/2000
• Issued: 02/12/2002
• 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
• Primary Examiner(s): Schuberg, Darren
• Assistant Examiner(s): ASSAF, FAYEZ G
• Application Number:
  US09/549,388
• Time in Patent Office: 669 Days
• Field of Search: 385/17, 385/18, 385/89, 359/223, 359/224, 359/872, 359/873
• US Class Current: 385/18
• 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 2011/0039 Electrical control
• CPC Class Codes: H04Q 2011/0049 Crosstalk reduction; Noise; Power budget
• CPC Class Codes: H04Q 2011/0058 Crossbar; Matrix

Abstract

The present invention provides a method and an optical cross connect (OXC) package which minimizes optical loss and crosstalk while also reducing the size of the package. The method includes directing a light beam from a first collimator of a plurality of collimators to a first micromirror of a plurality of micromirrors; folding the light beam from the first micromirror onto a second micromirror of the plurality of micromirrors; and directing the light beam from the second micromirror to a second collimator of the plurality of collimators, wherein a uniform redirection length is provided between each of the plurality of collimators and each of the plurality of micromirror. In the preferred embodiment, the OXC package comprises a first cap with reflecting surfaces and a second cap. With the first cap, only a short distance is used in redirecting the light. This allows for the major portion of the light to be available for scanning. With the second cap, the light beam is folded during the switching operation, resulting in a smaller switch package.

Claims

1. A method for performing an optical switching operation, comprising the steps of:

(a) directing a light beam from a first collimator of a plurality of collimators to a first micromirror of a plurality of micromirrors;

(b) folding the light beam from the first micromirror onto a second micromirror of the plurality of micromirrors; and

(c) directing the light beam from the second micromirror to a second collimator of the plurality of collimators, wherein a uniform redirection length is provided between each of the plurality of collimators and each of the plurality of micromirrors.

2. The method of claim 1, wherein the directing step (a) comprises:

(a1) directing the light beam from the first collimator to a first reflecting area on a first cap; and

(a2) directing the light beam from the first reflecting area to the first micromirror.

3. The method of claim 2, wherein the directing step (a1) comprises:

(a1i) directing the light beam from the first collimator, through a substrate, and to the first reflecting area.

4. The method of claim 1, wherein the folding step (b) comprises:

(b1) directing the light beam from the first micromirror to a second cap; and

(b2) directing the light beam from the second cap to the second micromirror.

5. The method of claim 1, wherein the directing step (c) comprises:

(c1) directing the light beam from the second micromirror to a second reflecting area on the first cap; and

(c2) directing the light beam from the second reflecting area to the second collimator.

6. A method for performing an optical switching operation, comprising the steps of:

(a) directing a light beam from a first collimator of a plurality of collimators to a first cap;

(b) directing the light beam from the first cap to a first micromirror of a plurality of micromirrors;

(c) directing the light beam from the first micromirror to a second cap;

(d) directing the light beam from the second cap to a second micromirror of the plurality of micromirrors;

(e) directing the light beam from the second micromirror to the first cap; and

(f) directing the light beam from the first cap to a second collimator of the plurality of collimators, wherein a uniform redirection length is provided between each of the plurality of collimators and each of the plurality of micromirrors.

7. The method of claim 6, wherein the directing step (a) comprises:

(a1) directing the light beam from the first collimator, through a substrate, and to a first reflecting area on the first cap.

8. The method of claim 6, wherein the directing step (b) comprises:

(b1) directing the light beam from a first reflecting area on the first cap to the first micromirror.

9. The method of claim 6, wherein the directing step (e) comprises:

(e1) directing the light beam from the second micromirror to a second reflecting area on the first cap.

10. The method of claim 6, wherein the directing step (f) comprises:

(f1) directing the light beam from a second reflecting area on the first cap to the second collimator.

11. A method for performing an optical switching operation, comprising the steps of:

(a) directing a light beam from a first collimator of a plurality of collimators to a first reflecting area on a first cap;

(b) directing the light beam from the first reflecting area to a first micromirror of a plurality of micromirrors.

(c) directing the light beam from the first micromirror to a second cap;

(d) directing the light beam from the second cap to a second micromirror of the plurality of micromirrors;

(e) directing the light beam from the second micromirror to a second reflecting area on the first cap; and

(f) directing the light beam from the second reflecting area to the second collimator, wherein a uniform redirection length is provided between each of the plurality of collimators and each of the plurality of micromirrors.

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

a plurality of collimators;

a plurality of micromirrors;

a first cap optically coupled between the plurality of collimators and the plurality of micromirrors, wherein a uniform redirection length is provided between each of the plurality of collimators and each of the plurality of micromirrors; and

a second cap optically coupled to the plurality of micromirrors.

13. The OXC of claim 12, further comprising:

a substrate, wherein a light beam may travel through the substrate, wherein the substrate comprising a first surface and a second surface, wherein the first surface is optically coupled to the plurality of collimators and the second surface is optically coupled to the first cap.

14. The OXC of claim 13, further comprising a plurality of photodetectors residing on the substrate at a location where the light beam travels in or out of the substrate.

15. The OXC of claim 13, further comprising:

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

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

16. The OXC of claim 13, wherein the substrate comprises a transparent slab transparent to wavelengths of interest.

17. The OXC of claim 13, wherein the substrate comprises holes through which the light beam may travel.

18. The OXC of claim 13, wherein the substrate comprises a double-sided polished wafer.

19. The OXC of claim 13, wherein the substrate comprises:

integrated circuits on the second surface of the substrate; and

conductive traces on the second surface of the substrate.

20. The OXC of claim 19, wherein the integrated circuits and conductive traces are absent from a path of the light beam traveling through the substrate.

21. The OXC of claim 12, wherein the plurality of micromirrors comprises a plurality of static mirrors.

22. The OXC of claim 12, wherein the plurality of micromirrors comprises a plurality of active mirrors.

23. The OXC of claim 12, wherein the plurality of micromirrors comprises a plurality of strips, wherein each of the plurality of strips comprises at least one of the plurality of micromirrors.

24. The OXC of claim 12, wherein the plurality of micromirrors comprises a plurality of input micromirrors and a plurality of output micromirrors.

25. The OXC of claim 12, wherein the plurality of micromirrors is a two dimensional array.

26. The OXC of claim 12, wherein the first cap further comprises:

a plurality of reflecting surfaces on a first surface of the first cap, wherein the plurality of reflecting surfaces directs the light beam between the plurality of collimators and the plurality of micromirrors.

27. The OXC of claim 26, wherein the plurality of reflecting surfaces comprises a plurality of flat mirrors.

28. The OXC of claim 26, wherein the plurality of reflecting surfaces comprises a plurality of curved mirrors.

29. The OXC of claim 26, further comprising:

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

30. The OXC of claim 12, further comprising:

a third cap optically coupled to the second cap, wherein a distance between the third cap and the second cap is approximately equal to a distance between the plurality of micromirrors and the second cap; and

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

31. The OXC of claim 30, further comprising a plurality of photodetectors residing on the third cap.

32. A system, comprising:

a fiber optic transmission system; and

a fiber optic cross connect (OXC) optically coupled to the fiber optic transmission system, the OXC comprising;

a plurality of collimators optically coupled to the fiber optic transmission system,

a plurality of micromirrors,

a first cap optically coupled between the plurality of collimators and the plurality of micromirrors, wherein a uniform redirection length is provided between each of the plurality of collimators and each of the plurality of micromirrors, and

a second cap optically coupled to the plurality of micromirrors.

33. A system, comprising:

an fiber optic cross connect (OXC); and

a light beam traversing through the OXC, wherein the light beam is directed from a first collimator of a plurality of collimators to a first micromirror of a plurality of micromirrors, folded from the first micromirror onto a second micromirror of the plurality of micromirrors, and directed from the second micromirror to a second collimator of the plurality of collimators, wherein a uniform redirection length is provided between each of the plurality of collimators and each of the plurality of micromirrors.