Structure for an optical switch on a silicon substrate

• US 6,466,356 B1
• Filed: 09/28/2000
• Issued: 10/15/2002
• Est. Priority Date: 09/28/2000
• Status: Expired due to Term

• Current Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Original Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Inventors: Peeters, Eric, Rosa, Michel A.
• Primary Examiner(s): Lester, Evelyn A
• Application Number:
  US09/675,108
• Time in Patent Office: 747 Days
• Field of Search: 359/290, 359/291, 359/298, 359/224, 257/415, 257/417-420
• US Class Current: 359/291
• CPC Class Codes: G02B 6/3518 the reflective optical element being an intrinsic part of a MEMS device, i.e. fabricated together with the MEMS device MEMS devices in general B81B; manufacture of MEM devices in general B81C; micromechanical devices controlling the direction of light G02B26/0833
• CPC Class Codes: G02B 6/3556 NxM switch, i.e. regular arrays of switches elements of matrix type constellation
• CPC Class Codes: G02B 6/358 Latching of the moving element, i.e. maintaining or holding the moving element in place once operation has been performed; includes a mechanically bistable system
• CPC Class Codes: G02B 6/3584 constructional details of an associated actuator having a MEMS construction, i.e. constructed using semiconductor technology such as etching MEMS per se B81B, B81C

Abstract

Optical cross-connect systems involve the general concept of a two dimensional array of MEMS tilt mirrors being used to direct light coming from a first optical fiber to a second optical fiber. Each MEMS tilt mirror in the two dimensional array can tilt about two non-colinear axes and is suspended by a plurality of suspension arms attached to a silicon substrate.

Claims

1. An actuatable mirror structure comprising:

a silicon substrate;

a plurality of metal suspension arms each comprising an internal stress gradient layer, each said plurality of metal suspension arms having a first end and a second end, said first end being attached to said silicon substrate;

a silicon area having a reflective surface layer, said silicon area being attached to said second end of said plurality of metal suspension arms; and

a plurality of electrodes arranged on said substrate adjacent to said plurality of metal suspension arms to create an electric field for producing deflective movement of said silicon area having said reflective surface layer.

2. The actuatable mirror structure of claim 1 wherein said plurality of suspension arms is three in number.

3. The actuatable mirror structure of claim 1 wherein said silicon area has a substantially square shape.

4. The actuatable mirror structure of claim 1 wherein said internal stress gradient layer comprises MoCr.

5. The actuatable mirror structure of claim 4 wherein an internal stress gradient is on the order of 3 gigapascal across said stress gradient layer.

6. An array of actuatable mirror structures, wherein each of said actuatable mirror structures comprises a structure in accordance with claim 1.

7. The array of claim 6 wherein said array is a two dimensional rectilinear array.

8. The actuatable mirror structure of claim 1 wherein each of said plurality of electrodes has a substantially tapered shape.

9. An actuatable mirror structure comprising:

a silicon substrate;

four metal suspension arms each comprising an internal stress gradient layer, each of said four metal suspension arms having a first end and a second end, said first end being attached to said silicon substrate;

a silicon area having a reflective surface layer, said silicon area being attached to said second end of said four metal suspension arms; and

four electrodes arranged on said silicon substrate adjacent to said four metal suspension arms, respectively, to create an electric field for producing deflective movement of said silicon area having said reflective gold surface layer.

10. An array of actuatable mirror structures, wherein each of said actuatable mirror structures comprises a structure in accordance with claim 9.

11. The array of claim 10 wherein said array is a two dimensional rectilinear array.

12. An actuatable mirror structure comprising:

a silicon substrate having a cutout portion;

a plurality of metal suspension arms each comprising an internal stress gradient layer, each said plurality of metal suspension arms having a first end and a second end, said first end being attached to said silicon substrate;

a silicon area having a reflective surface layer and positioned over said cutout portion, said silicon area being attached to said second end of said plurality of metal suspension arms; and

a plurality of electrodes arranged on said substrate adjacent to said plurality of metal suspension arms to create an electric field for producing deflective movement of said silicon area having said reflective surface layer.

13. The structure of claim 12 wherein said reflective surface layer is gold.

14. An array of actuatable mirror structures, wherein each of said actuatable mirror structures comprises a structure in accordance with claim 12.

15. The array of claim 14 wherein said array is a two dimensional rectilinear array.