Mechanically assisted release for MEMS optical switch

• US 6,643,426 B1
• Filed: 09/28/2000
• Issued: 11/04/2003
• Est. Priority Date: 10/19/1999
• Status: Expired due to Fees

• Current Assignee: Corning Incorporated
• Original Assignee: Corning Incorporated
• Inventors: McDonald, Terrance G.
• Primary Examiner(s): Sanghavi, Hemang
• Assistant Examiner(s): Song, Sarah U
• Application Number:
  US09/675,331
• Time in Patent Office: 1,132 Days
• Field of Search: 385/16-23
• US Class Current: 385/18
• CPC Class Codes: G02B 26/004 based on a displacement or a deformation of a fluid
• CPC Class Codes: G02B 6/3514 the reflective optical element moving along a line so as to translate into and out of the beam path, i.e. across the beam path
• CPC Class Codes: G02B 6/3544 2D constellations, i.e. with switching elements and switched beams located in a plane
• 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 6/3596 With planar waveguide arrangement, i.e. in a substrate, regardless if actuating mechanism is outside the substrate

Abstract

An optical switch is disclosed that includes a pixel member that moves between a quiescent switch state and an active switch state. An assisted-release mechanism is coupled to the pixel member. It applies a force to the pixel member in the active switch state to enhance the response time of the switch when being reset to the quiescent switch state.

Claims

1. An optical switch for directing at least one light signal, the optical switch including an optical substrate having at least one trench formed at the intersection of at least one first waveguide and at least one second waveguide, and an electrical substrate coupled to the optical substrate, the electrical substrate having at least one actuator disposed opposite to the at least one trench, the optical switch comprising:

at least one pixel coupled to the optical substrate and interposed between the trench and the actuator, the at least one pixel moving between a first quiescent switch state and a second active switch state and wherein the at least one pixel further comprises;

a plate coupled to the optical substrate, the plate being interposed between the trench and the actuator; and

a reflector connected to the plate; and

an assisted-release mechanism coupled to the pixel member, the assisted-release mechanism applying a force to the pixel member in the second active state_wherein the assisted-release mechanism further comprises;

at least one landing post disposed on the electrical substrate, the landing post engaging the pixel in the second switch state; and

at least one flexure spring coupled to the pixel, the flexure spring being deflected by the landing post in the second state to thereby store mechanical energy.

2. The optical switch of claim 1, wherein the reflector is disposed in the trench in the first state to thereby reflect the at least one light signal propagating in the at least one first waveguide into the at least one second waveguide.

3. The optical switch of claim 2, wherein the reflector is disposed in the trench in the first state when the actuator is quiescent.

4. The optical switch of claim 1, wherein the reflector is retracted from the trench in the second state to thereby allow the at least one light signal to propagat e in the at least one first waveguide after passing through the trench without being reflected by the reflector.

5. The optical switch of claim 1, wherein the reflector is retracted from the trench when the actuator causes the plate to move toward the electrical substrate in the second switch state.

6. The optical switch of claim 5, wherein the actuator causes the plate to move by electrostatic attraction.

7. The optical switch of claim 5, wherein the force applied by the assisted-release mechanism moves the pixel away from the electrical substrate when the actuator switches from the second state to the first state by returning to a quiescent condition.

8. The optical switch of claim 1, wherein the flexure spring is connected to the plate.

9. The optical switch of claim 1, wherein the flexure spring is connected to the landing post.

10. The optical switch of claim 1, wherein the stored mechanical energy is released to apply a force to move the pixel away from the electrical substrate when the actuator switches from the second state to the first state by returning to a quiescent condition.

11. The optical switch of claim 1, wherein the at least one landing post includes a plurality of adjustable landing posts, the height of the adjustable landing posts being adjustable to thereby align the pixel member.

12. The optical switch of claim 1, wherein the at least one actuator further comprises:

an electrode dispose on the electrical substrate, the electrode applying an electrostatic attractive force to the pixel when energized in the second switch state; and

aplurality of stopper elements disposed on the electrical substrate, the stopper elements adapted to prevent the pixel from contacting the electrode.

13. The optical switch of claim 12, wherein the electrode is substantially de-energized in the first switch state.

14. The optical switch of claim 12, wherein the at least one actuator further comprises a landing post, the landing post engaging the assisted-release mechanism in the second switch state to thereby store mechanical energy.

15. The optical switch of claim 14, wherein the stored mechanical energy is released, applying a force to thereby move the pixel away from the actuator when the electrode stops applying the electrostatic attractive force to the pixel.

16. The optical switch of claim 1, wherein an index-matching fluid is disposed in the trench to prevent the at least one light signal from de-collimating when it propagates through the trench.

17. The optical switch of claim 1, wherein the at least one trench includes an array of trenches formed in the optical substrate, each of the trenches being formed at the intersection of a first waveguide and a second waveguide, the electrical substrate also includes an array of actuators, each actuator being disposed opposite a corresponding trench, and the at least one pixel includes an array of pixels, each pixel being interposed between a corresponding trench and actuator.

18. A method for switching a light signal in an optical switch, the optical switch including a pixel movable between a light redirecting state and a non-redirecting state, and an actuator that applies a force to the pixel to thereby move the pixel from the redirecting state to the non-redirecting state, the method comprising the steps of:

providing an assisted-release mechanism;

pressing the assisted-release mechanism to the pixel member in the non-redirecting state to thereby store potential energy; and

releasing the potential energy when the actuator ceases to apply the force to the pixel, whereby the assisted-release mechanism urges the pixel to move from the non-redirecting state to the redirecting state; and

wherein the step of providing further comprises the steps of providing a landing post juxtaposed to an electrode, the landing post directly contacting the pixel in the non-redirecting state, and providing a flexure spring coupled to the pixel.

19. The method of claim 18, wherein the step of pressing includes pressing the flexure spring against the landing post in the non-redirecting state to thereby store the potential energy.

20. The method of claim 18, wherein the step of providing the flexure spring includes metal deposition.

21. The method of claim 20, wherein the metal is aluminum.

22. The method of claim 18, wherein the step of providing the landing post includes providing a material having low mechanical stiction.

23. The method of claim 22, wherein the material is a photoresist material.