Optical switch with low-inertia micromirror

• US 6,801,681 B2
• Filed: 01/17/2001
• Issued: 10/05/2004
• Est. Priority Date: 01/17/2001
• Status: Expired due to Fees

• Current Assignee: Innovative Micro Technology Incorporated, JDS Uniphase Corporation (Lumentum Holdings Inc.), International Engine Intellectual Property Company, LLC (Volkswagen AG)
• Original Assignee: Optical Coating Laboratory, Inc. (Lumentum Holdings Inc.)
• Inventors: Stocker, John W., Rybnicek, Kimon, Rubel, Paul J., Martin, Richard T., Hichwa, Bryant P., Foster, John S., Feierabend, Patrick E., Summers, Jeffery F.
• Primary Examiner(s): Sanghavi, Hemang
• Application Number:
  US09/765,520
• Publication Number:
  US 20020094152A1
• Time in Patent Office: 1,357 Days
• Field of Search: 385/16-21, 385/24, 359/280, 359/290, 359/298, 359/318, 359/320, 359/40.MM, 310/40.MM
• US Class Current: 385/18
• CPC Class Codes: G02B 2006/12104 Mirror; Reflectors or the like
• CPC Class Codes: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means
• CPC Class Codes: G02B 26/085 the reflecting means being moved or deformed by electromagnetic means
• 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 6/3564 Mechanical details of the actuation mechanism associated with the moving element or mounting mechanism details
• 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: G02B 6/4226 Positioning means for moving the elements into alignment, e.g. alignment screws, deformation of the mount

Abstract

An optical switch is fabricated using micro-electro-mechanical system (“MEMS”) techniques. A thin mirror is fabricated in the major plane of the substrate and rotates about an axis perpendicular to the major plane to move into and out of an optical beam path. The mirror surface is open for chemical polishing and deposition, resulting in a high-quality mirror. In one embodiment, the backside of the mirror is patterned with reinforcing ribs. In another embodiment, a two-sided mirror is fabricated.

Claims

1. A micro-electro-mechanical system (“

MEMS”

) optical switch comprising;

a base portion of a die attached to

a pivoting member with

a hinge, the pivoting member rotating in relation to the base portion about an axis essentially perpendicular to a major surface of the die;

a mirror having a mirror surface essentially parallel to the major surface of the die, the mirror being integrated with the pivoting member; and

an actuator disposed to rotate the pivoting member to move the mirror from a first switch position to a second switch position.

7. The optical switch of claim 1 wherein the actuator is a magnetic drive.

12. The optical switch of claim 1 wherein the hinge and the mirror arc formed from single-crystal silicon.

13. The optical switch of claim 12 wherein the hinge and the mirror are formed in a layer of single-crystal silicon about 10-80 microns thick.

14. The optical switch of claim 12 wherein the mirror comprises a metallic film formed on the layer of single-crystal silicon.

15. The optical switch of claim 12 wherein the mirror comprises a thin section and a rib section, the rib section being thicker than the thin section.

16. The optical switch of claim 15 wherein the rib section has a first thickness and the thin section has a second thickness, the first thickness being about twice the second thickness.

17. The optical switch of claim 16 wherein the first thickness is about 40 microns and the second thickness is about 20 microns.

2. A micro-electro-mechanical system (“

MEMS”

) optical switch comprising;

a base portion of a die attached to

a pivoting member with

a hinge, the pivoting member rotating in relation to the base portion about an axis essentially perpendicular to a major surface of the die;

a mirror having a mirror surface essentially parallel to the major surface of the die, the mirror being integrated with the pivoting member;

an actuator disposed to rotate the pivoting member to move the mirror from a first switch position to a second switch position; and

a latching spring connected to the base portion and to the pivoting member.

3. The optical switch of claim 2 wherein the latching spring is a radial spring having a first arc of motion and the pivoting member has a second arc of motion, a the first switch position corresponding to a first intersection of the first arc of motion and the second arc of motion and the second switch position corresponding to a second intersection of the first arc of motion and the second arc of motion.

4. The optical switch of claim 3 wherein the binge is connected to the base portion with a hinge post and the axis is offset from the hinge post.

5. A micro-electro-mechanical system (“

MEMS”

) optical switch comprising;

a base portion of a die attached to

a pivoting member with

a hinge, the pivoting member rotating in relation to the base portion about an axis essentially perpendicular to a major surface of the die;

a mirror having a mirror surface essentially narallel to the major surface of the die, the mirror being integrated with the pivoting member; and

an actuator disposed to rotate the pivoting member to move the minor from a first switch position to a second switch position, wherein at least a portion of the mirror in the first switch position extends beyond an edge of the die.

6. The optical switch of claim 5 wherein the portion of the mirror extending beyond the edge of the die extends at least about 400 microns.

8. A micro-electro-mechanical system (“

MEMS”

) optical switch comnrising;

a base portion of a die attached to

a pivoting member with

a hinge, the pivoting member rotating in relation to the base portion about an axis essentially perpendicular to a major surface of the die;

a mirror having a mirror surface essentially parallel to the major surface of the die, the mirror being integrated with the pivoting member; and

a magnetic drive disposed to rotate the pivoting member to move the mirror from a first wherein the magnetic drive comprises

a first pole disposed on the base portion;

a second pole disposed on the base portion; and

a magnetic tab disposed on the pivoting member and movable within a gap formed between the first pole and the second pole.

9. The optical switch of claim 8 wherein the first pole, the second pole, and the magnetic tab comprise an alloy consisting essentially of 45% nickel and 55% iron.

10. The optical switch of claim 8 further comprising

a first sensing pole disposed on the base portion and

a second sensing pole disposed on the base portion.

11. The optical switch of claim 10 further comprising

a first core segment disposed on the base portion;

a first pinched region disposed between and magnetically coupling the first core segment and the first sensing pole;

a second core segment disposed on the base portion; and

a second pinched region disposed between and magnetically coupling the first core segment and the first sensing pole.

18. A micro-electro-mechanical system (“

MEMS”

) optical switch comprising;

a base portion of a die attached to

a pivoting member with

a hinge from single-crystal silicon, the pivoting member rotating in relation to the base portion about an axis essentially perpendicular to a major surface of the die;

a mirror integrated with the pivoting member and formed from single-crystal silicon having a mirror surface essentially parallel to the major surface of the die and a plurality of ribs disposed on a backside of the mirror, the mirror comprising a rib section having a first thickness and a thin section having a second thickness, the first thickness being about twice the second thickness; and

an actuator disposed to rotate the pivoting member to move the mirror from a first switch position to a second switch position.

19. A micro-electro-mechanical system (“

MEMS”

) optical switch comprising;

a base portion of a die attached to

a pivoting member with

a hinge, the pivoting member rotating in relation to the base portion about an axis essentially perpendicular to a major surface of the die;

a mirror having a first mirrored surface and a second mirrored surface essentially parallel to the major surface of the die, the mirror being integrated with the pivoting member; and

an actuator disposed to rotate the pivoting member to move the mirror from a first switch position to a second switch position.

20. A micro-electro-mechanical system (“

MEMS”

) optical switch comprising;

a base portion of a die attached to a pivoting member with

a hinge, the pivoting member rotating in relation to the base portion about an axis essentially perpendicular to a major surface of the die;

a mirror having a mirror surface essentially parallel to the major surface of the die defining an oval of about 1.4×

1.0 mm, the mirror being integrated with the pivoting member; and

an actuator disposed to rotate the pivoting member to move the mirror from a first switch position to a second switch position.

21. A micro-electro-mechanical system (“

MEMS”

) optical switch comprising;

a base portion of a diet attached to

a pivoting member with

a hinge, the pivoting member rotating in relation to the base portion about an axis essentially perpendicular to a major surface of the die;

a mirror having a mirror surface essentially parallel to the major surface of the die defining an oval of about 780×

550 microns, the mirror being integrated with the pivoting member; and

an actuator disposed to rotate the pivoting member to move the mirror from a first switch position to a second switch position.

22. A micro-electro-mechanical system (“

MEMS”

) optical switch comprising;

a base portion of a die attached to

a pivoting member formed in a layer of single-crystal silicon with

a hinge formed of the layer of single-crystal silicon, the pivoting member rotating in relation to the base portion about an axis essentially perpendicular to a major surface of the die;

a mirror formed from the layer of single-crystal silicon and a metallic coating having a mirror surface essentially parallel to the major surface of the die, the mirror being integrated with the pivoting member; and

an actuator configured to rotate the pivoting member and mirror with respect to the base portion in response to a control signal.

23. A micro-electro-mechanical system (“

MEMS”

) optical switch comprising;

a base portion of a die attached to

a pivoting member formed in a layer of single-crystal silicon with

a hinge formed of the layer of single-crystal silicon, the pivoting member rotating in relation to the base portion about an axis essentially perpendicular to a major surface of the die;

a mirror formed from the layer of single-crystal silicon and a reflective coating having a mirror surface essentially parallel to the major surface of the die, the mirror being integrated with the pivoting member;

a latching spring disposed between the base portion and the pivoting member to hold the pivoting member in one of a first position and a second position; and

a magnetic drive including a first pole and a second pole disposed on the base portion, the first pale and the second pole forming a gap therebetween in at least the single-crystal silicon layer and further including a magnetic tab disposed on an arm movable within the gap.