Structure for an optical switch on a glass substrate

• US 6,411,427 B1
• Filed: 09/28/2000
• Issued: 06/25/2002
• 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: Fork, David K., Peeters, Eric, Rosa, Michel A.
• Primary Examiner(s): Spyrou, Cassandra
• Assistant Examiner(s): Robinson, Mark A.
• Application Number:
  US09/675,945
• Time in Patent Office: 635 Days
• Field of Search: 359/846, 359/849, 359/223, 359/224, 359/290, 359/291, 359/298
• US Class Current: 359/298
• 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
• CPC Class Codes: Y10S 359/904 Micromirror

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 glass substrate.

Claims

1. An actuatable mirror structure comprising:

a substrate with a top surface in a first plane;

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

a metal area having a reflective surface layer, said metal area being integrally attached to said second ends of said plurality of metal suspension arms, the internal stress gradient layer to produce sufficient stress in said plurality of metal suspension arms to maintain the reflective surface layer in a second plane that is different from said first plane; 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 metal 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 substrate is glass.

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. The actuatable mirror structure of claim 1 wherein said metal area has a substantially octagonal shape.

7. The actuatable mirror structure of claim 1 wherein said metal area is comprised of two MoCr layers having internal stress gradients acting in opposite directions.

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

9. The array of claim 8 wherein said array is a two dimensional rectilinear array.

10. The actuatable mirror structure of claim 1 wherein each of said plurality of electrodes extends underneath said metal area.

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

12. The actuatable mirror structure of claim 1 wherein the first plane and the second plane are parallel when the plurality of electrodes are not producing an electric field.

13. An actuatable mirror structure comprising:

a glass substrate;

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

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

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

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

15. An array of actuatable mirror structures, wherein each of said actuatable mirror structures comprises a structure in accordance with claim 13.

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