Modular approach to substrate population in a fiber optic cross connect

• US 6,430,330 B1
• Filed: 04/14/2000
• Issued: 08/06/2002
• 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): Spyrou, Cassandra
• Assistant Examiner(s): ASSAF, FAYEZ G
• Application Number:
  US09/549,799
• Time in Patent Office: 844 Days
• Field of Search: 385/17, 385/18, 385/16, 359/223, 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: H04Q 11/0003 Details
• CPC Class Codes: H04Q 2011/0024 using space switching
• CPC Class Codes: H04Q 2011/0026 using free space propagation (e.g. lenses, mirrors)

Abstract

The present invention provides a fiber optic cross connect (OXC) package which utilizes a modular approach to substrate population. The OXC includes a slab, where the slab comprises a first surface and a second surface, and a micromirror array coupled to the second surface of the slab, where the micromirror array comprises a plurality of clusters, where each of the plurality of clusters includes at least one micromirror of the micromirror array. In the preferred embodiment, the slab is a substrate. Chips containing micromirrors are fabricated in clusters so that groups of micromirrors can be separately placed onto the substrate. This provides flexibility in how the substrate is populated. In the preferred embodiment, the clusters are in the form of strips. Only strips with known good micromirrors are placed onto the substrate, thus improving the device yield. Also, if any of the micromirrors become damaged after placement, its chip may be replaced without disturbing the other chips. Using a substrate through which light may travel 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, wherein the substrate comprises a first surface and a second surface, wherein the substrate comprises holes through which the light beams travel; and

a micromirror array coupled to the second surface of the substrate, wherein the micromirror array comprises a plurality of clusters, wherein each of the plurality of clusters comprises at least one micromirror of the micromirror array.

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

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

4. The OXC of claim 1, wherein each of the plurality of clusters is in a shape of a strip.

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

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

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

8. A fiber OXC, comprising:

a slab, wherein the slab comprises a first surface and a second surface;

a micromirror array coupled to the second surface of the slab, wherein the micromirror array comprises a plurality of clusters, wherein each of the plurality of clusters comprises at least one micromirror of the micromirror array;

integrated circuits coupled to the first or second surfaces of the slab; and

conductive traces coupled to the first or second surfaces of the slab, wherein the integrated circuits and the conductive traces coupled to the second surface of the slab are absent from paths of light beams traveling through the slab.

9. A fiber OXC, comprising:

a slab, wherein the slab comprises a first surface and a second surface, wherein the slab is transparent to wavelengths of interest; and

a micromirror array coupled to the second surface of the slab, wherein the micromirror array comprises a plurality of clusters, wherein each of the plurality of clusters comprises at least one micromirror of the micromirror array.

10. A fiber OXC, comprising:

a slab, wherein the slab comprises a first surface and a second surface, wherein the slab comprises;

a first anti-reflective coating on the first surface of the slab, and

a second anti-reflective coating on the second surface of the slab; and

a micromirror array coupled to the second surface of the slab, wherein the micromirror array comprises a plurality of clusters, wherein each of the plurality of clusters comprises at least one micromirror of the micromirror array.

11. A fiber OXC, comprising:

a slab, wherein the slab comprises a first surface and a second surface;

a micromirror array coupled to the second surface of the slab, wherein the micromirror array comprises a plurality of clusters, wherein each of the plurality of clusters comprises at least one micromirror of the micromirror array;

a housing, the housing containing a plurality of optical fibers, wherein the plurality of optical fibers are each optically coupled to the first surface of the slab; and

a plurality of collimators within the housing and optically coupled to the plurality of optical fibers.

12. The OXC of claim 11, further comprising:

a first cap optically coupled to the micromirror array, wherein the first cap is parallel to the first and second surfaces of the slab;

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

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

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

13. 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 reflects the light beams from the plurality of collimators to the micromirror array and from the micromirror array to the plurality of collimators.

14. The OXC of claim 13, 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.

15. The OXC of claim 13, 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 to the second surface of the first cap.

16. The OXC of claim 13, wherein the plurality of reflecting surfaces comprises a plurality of flat mirrors.

17. The OXC of claim 13, wherein the plurality of reflecting surfaces comprises a plurality of curved mirrors.

18. 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 micromirror array and the second cap;

and

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

19. The OXC of claim 18, further comprising a plurality of photodetectors residing on the third cap.

22. The OXC of claim 11, further comprising:

a plurality of collimators within the housing and optically coupled to the plurality of optical fibers.

20. A fiber OXC, comprising:

a slab, wherein the slab comprises a first surface and a second surface;

a micromirror array coupled to the second surface of the slab, wherein the micromirror array comprises a plurality of clusters, wherein each of the plurality of clusters comprises at least one micromirror of the micromirror array; and

a plurality of photodetectors residing on the slab at a location where light beams travel in or out of the slab.

21. A system, comprising:

a fiber optic transmission system; and

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

a slab optically coupled to the fiber optic transmission system, wherein the slab comprises a first surface and a second surface, wherein the slab is transparent to wavelengths of interest, and

a micromirror array coupled to the second surface of the slab, wherein the micromirror array comprises a plurality of clusters, wherein each of the plurality of clusters comprises at least one micromirror of the micromirror array.