Electrically actuated optical switch having a surface pivotable Mirror

• US 6,362,556 B1
• Filed: 02/16/2001
• Issued: 03/26/2002
• Est. Priority Date: 03/30/1999
• Status: Expired due to Fees

• Current Assignee: Agilent Technologies, Inc.
• Original Assignee: Agilent Technologies, Inc.
• Inventors: Hoen, Storrs T.
• Primary Examiner(s): Dougherty, Thomas M.
• Application Number:
  US09/785,004
• Publication Number:
  US 20020047490A1
• Time in Patent Office: 403 Days
• Field of Search: 310/309
• US Class Current: 310/309
• 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 6/3546 NxM switch, i.e. a regular array of switches elements of matrix type constellation
• CPC Class Codes: G02B 6/3566 involving bending a beam, e.g. with cantilever
• CPC Class Codes: G02B 6/357 Electrostatic force electrostatic forces controlling reflecting elements in general G02B26/0841
• 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: H02N 1/006 of the gap-closing type H02N1/004 takes precedence

Abstract

An optical switch uses a surface electrostatic actuator to mechanically pivot a reflector to selectively redirect a received optical beam. In one application, the optical switch selectively couples a first optical fiber to a second optical fiber. The electrostatic actuator includes first and second members that are separated by a short distance. The opposing surfaces of the two members include a number of drive electrodes. These electrodes generate electrostatic forces which induce lateral displacement when the electrostatic forces are modified. The modification of the electrostatic forces is accomplished by reconfiguring a voltage pattern of the drive electrodes. The lateral displacement pivots the reflector, which is mechanically attached to the first member. The pivoting occurs along a pivot region that is generally parallel to the surfaces of the first and second members. The first member may be a stator, while the second member may be a translator that controls pivoting of an internal micromirror.

Claims

1. An optical switch for manipulating an optical beam comprising:

a first member;

a second member supported in spaced relation from a surface of said first member by flexures;

arrays of electrodes distributed along each of said first and second members to enable electrostatic drive forces to selectively displace said second member relative to said first member; and

a reflector connected to each of said first and second members to pivot about a pivot axis that is generally parallel to said surface of said first member as responses to relative displacements between said first and second members, said reflector having a plurality of operation positions, including at least one operation position within a path of said optical beam.

2. The optical switch of claim 1 wherein said reflector resides within an interior region of said second member.

3. The optical switch of claim 2 wherein said second member is a movable member and said first member is a stationary member, said movable member having an opening in which said reflector is seated.

4. The optical switch of claim 1 wherein said reflector is mounted to said second member by a strip of flexible material that defines said pivot axis.

5. The optical switch of claim 4 wherein said strip of flexible material is silicon nitride.

6. The optical switch of claim 1 wherein said arrays of electrodes include electrostatic drive electrodes on each of said first and second members.

7. The optical switch of claim 6 wherein said arrays of electrodes further include levitation electrodes on each of said first and second members, said levitation electrodes being generally perpendicular to said electrostatic drive electrodes.

8. The optical switch of claim 6 further comprising a means for stepping a pattern of voltages along at least one of said arrays of electrostatic drive electrodes of said first and second members.

9. The optical switch of claim 1 further comprising a source of said optical beam, said source being a fiber.

10. An optical switch comprising:

an input path for an optical beam;

a pivoting reflector having first and second positions, at least one of said first and second positions being along said input path;

a first member, said pivoting reflector being mounted to said first member to pivot between said first and second positions along a pivot region that is generally parallel to said first member; and

a second member connected to said first member to enable substantially linear movement parallel to said first member, said second member being connected to said pivoting reflector to induce said pivot between said first and second positions in response to said substantially linear movement, said first and second members having an electrostatic-drive relationship such that said substantially linear movement is induced by electrostatic forces generated therebetween.

11. The optical switch of claim 10 wherein said pivoting reflector is mounted to said first member by a flexible strip of material which forms said pivot region.

12. The optical switch of claim 11 wherein said flexible strip is silicon nitride.

13. The optical switch of claim 10 wherein said first member is stationary and includes a first plurality of electrostatic drive electrodes and wherein said second member is a movable member having a second plurality of electrostatic drive electrodes that are responsive to voltage patterns along said first plurality.

14. The optical switch of claim 13 wherein said first and second members are spaced apart by flexures which have flexing characteristics which enable said substantially linear movement.

15. The optical switch of claim 10 wherein said second member has an interior region in which said pivoting reflector is supported.

16. The optical switch of claim 15 wherein said first position of said pivoting reflector is one in which said pivoting reflector is misaligned with said input path.

17. The optical switch of claim 16 wherein said input path includes wave-guides formed of materials on said first member.