Method and structure for a slug assisted pusher-mode piezoelectrically actuated liquid metal optical switch

• US 6,818,844 B2
• Filed: 04/14/2003
• Issued: 11/16/2004
• Est. Priority Date: 04/14/2003
• Status: Expired due to Fees

• Current Assignee: Avago Technologies General IP PTE Limited (Broadcom, Inc.)
• Original Assignee: Agilent Technologies, Inc.
• Inventors: Fong, Arthur, Wong, Marvin Glenn
• Primary Examiner(s): Friedhofer, Michael A.
• Application Number:
  US10/413,070
• Publication Number:
  US 20040200708A1
• Time in Patent Office: 582 Days
• Field of Search: 200/182, 200/187-189, 200/209-219, 200/233-236, 310/328, 310/331, 310/348, 310/363, 335/4, 335/47, 335/48, 385/19
• US Class Current: 200/182
• CPC Class Codes: H01H 2029/008 using micromechanics, e.g. micromechanical liquid contact switches or [LIMMS]
• CPC Class Codes: H01H 2057/006 Micromechanical piezoelectric relay
• CPC Class Codes: H01H 29/28 with level of surface of contact liquid displaced by fluid pressure
• CPC Class Codes: H01H 57/00 Electrostrictive relays; Piezoelectric relays

Abstract

A method and structure for an optical switch. According to the structure of the present invention, a liquid-filled chamber is housed within a solid material. A plurality of seal belts within the liquid-filled chamber are coupled to the solid material, while a plurality of piezoelectric elements are coupled to a plurality of membranes. The plurality of membranes are coupled to the liquid-filled chamber, and a plurality of optical waveguides are coupled to the liquid-filled chamber. The plurality of seal belts are coupled to a plurality of liquid metal globules, wherein one or more of the plurality of liquid metal globules are coupled to a slug. According to the method, one or more piezoelectric elements are actuated, causing one or more corresponding membrane elements to be deflected. The deflection of the membrane element changes a pressure of actuator liquid and the change in pressure of the actuator liquid breaks a liquid metal connection between a first contact and a second contact of the electrical switch and breaks a slug connection between the first contact and the second contact. The breaking of the liquid metal connection and a movement of the slug is operable to block or unblock one or more of the plurality of optical waveguides.

Claims

1. A structure for an optical switch, comprising:

a chamber housed within a solid material, said chamber having an actuator liquid;

a plurality of seal belts within the chamber, wherein the plurality of seal belts are coupled to the solid material;

a plurality of liquid metal globules, coupled to the plurality of seal belts and coupled to the chamber;

a slug, coupled to one or more of the plurality of liquid metal globules and coupled to one or more of the plurality of switch contacts;

a plurality of piezoelectric elements coupled to a plurality of membranes, said plurality of membranes coupled to the chamber; and

a plurality of optical waveguides coupled to the chamber, said plurality of optical waveguides operable to be blocked or unblocked by the slug.

2. The structure of claim 1, wherein the actuator liquid is inert, low viscosity, and electrically non-conductive.

3. The structure of claim 1, wherein the slug is solid.

4. The structure of claim 1, wherein the slug is encapsulated within a liquid metal globule of the plurality of liquid metal globules.

5. The structure of claim 1, wherein the plurality of optical waveguides have faces that are not wettable.

6. The structure of claim 1, wherein the actuating liquid is 3M Fluorinert.

7. The structure of claim 1, wherein the plurality of piezoelectric elements are within one or more reservoirs, said one or more reservoirs containing actuating liquid operable to replenish the actuator fluid in the chamber.

8. The structure of claim 1, wherein the one or more liquid metal globules are composed of mercury.

9. The structure of claim 1, wherein the one or more liquid metal globules are composed of gallium alloys.

10. The structure of claim 1, wherein the plurality of membranes are coupled to a corresponding plurality of vias, wherein a via of the plurality of vias is operable to increase a rate of flow of the actuating liquid.

11. The structure of claim 10, wherein the plurality of vias are oriented so that a via is located between a longitudinal end of the channel and a seal belt of the plurality of seal belts.

12. The structure of claim 1, wherein the plurality of membranes have a corresponding plurality of widths, said corresponding plurality of widths being greater than an extent in a non-actuating direction of the plurality of piezoelectric elements.

13. The structure of claim 1, wherein the plurality of piezoelectric elements are further coupled to a corresponding plurality of contacts, said plurality of contacts operable to actuate the plurality of piezoelectric elements.

14. The structure of claim 13, wherein each contact of the plurality of contacts comprise a first terminal coupled to a first end of a piezoelectric element and a second terminal coupled to a second end of the piezoelectric element.

15. The structure of claim 14, wherein the first terminal and the second terminal are separated by a dielectric.

16. A structure for an optical switch, comprising:

a piezoelectric substrate layer;

an actuator fluid reservoir layer coupled to the piezoelectric substrate layer, said actuator fluid reservoir layer further comprising a plurality of piezoelectrically actuated pusher elements;

a chamber layer coupled to the actuator fluid reservoir layer, said chamber layer comprising a plurality of membranes coupled to the plurality of piezoelectrically actuated pusher elements;

a via layer coupled to the chamber layer, wherein said via layer comprises a plurality of vias;

a liquid metal channel layer coupled to the via layer, said liquid metal channel layer coupled to a plurality of optical waveguides; and

an actuator liquid-filled chamber housed within the liquid metal channel layer, wherein the actuator liquid-filled chamber comprises one or more globules of liquid metal coupled to a plurality of seal belts and a slug coupled to one or more of the one or more globules of liquid metal and coupled to one or more of the one or more seal belts, wherein said actuator liquid-filled chamber is coupled to the one or more membranes.

17. The structure of claim 16, wherein the plurality of seal belts are coupled to the circuit substrate layer.

18. The structure of claim 16, wherein the chamber layer, via layer, piezoelectric substrate layer, actuator fluid reservoir layer, and liquid metal channel layer may be composed of one or more of glass, ceramic, composite material and ceramic-coated material.

19. The structure of claim 16, wherein the slug is encapsulated within a liquid metal globule of the one or more liquid metal globules.

20. The structure of claim 16, wherein the plurality of optical waveguides have faces that are not wettable.

21. The structure of claim 16, wherein the actuator fluid reservoir layer further comprises a fill port, said fill port operable to be used for filling a reservoir of the actuator fluid reservoir layer with actuator fluid.

22. The structure of claim 16, wherein the circuit substrate layer further comprises a plurality of circuit traces and a plurality of pads operable to route one or more signals generated by actuation of one or more of the plurality of piezoelectric elements.

23. The structure of claim 16, wherein the actuator liquid is inert, low viscosity, and electrically non-conductive.

24. The structure of claim 16, wherein the one or more liquid metal globules are composed of mercury.

25. The structure of claim 16, wherein the plurality of vias are operable to increase a rate of flow of the actuating liquid and a further operable to change a velocity of the slug.

26. The structure of claim 16, wherein the membrane layer further comprises one or more fluid ports, said one or more fluid ports operable to replenish an amount of actuator fluid in a fluid chamber of the chamber layer from a one or more reservoirs of the actuator fluid reservoir layer.

27. The structure of claim 26, wherein the one or more fluid ports have a size that enables the replenish of the actuator fluid without substantially reducing a rate of flow of actuator fluid into the actuator liquid-filled chamber.

28. The structure of claim 16, wherein the plurality of piezoelectric elements are further coupled to a corresponding plurality of contacts, said plurality of contacts operable to actuate the plurality of piezoelectric elements.

29. The structure of claim 28, wherein each contact of the plurality of contacts comprises a first terminal coupled to a first end of a piezoelectric element and a second terminal coupled to a second end of the piezoelectric element.

30. The structure of claim 29, wherein the first terminal and the second terminal are separated by a dielectric.

31. A method for switching of one or more optical signals using a liquid metal switch, comprising:

actuating one or more piezoelectric elements;

deflecting one or more corresponding membrane elements by the actuation of the one or more piezoelectric elements;

changing a pressure of actuator liquid by the deflection of the one or more membrane elements; and

the change in pressure of the actuator liquid breaking a liquid metal connection between a first contact and a second contact of the liquid metal switch, moving a slug coupled to the first contact and coupled to the second contact, thereby blocking or unblocking one or more of a plurality of optical waveguides.

32. The method of claim 31, wherein the piezoelectric element is actuated by an application of an electric potential applied to a first side and a second opposite side of the piezoelectric element.

33. The method of claim 31, wherein the liquid metal connection is maintained by a surface tension between a liquid metal and the first contact and the second contact.

34. The method of claim 31, wherein the slug is coupled to a contact by the wettability of the slug and the presence of liquid metal on the slug.

35. The method of claim 31, wherein prior to an operation of the electrical switch, actuator fluid is added to the liquid metal switch using a fill port.

36. The method of claim 31, wherein one or more vias coupled to the one or more membranes are used to increase a flow rate of actuator liquid caused by the increase in pressure, said increased flow rate operable to more rapidly break the liquid metal connection and change a velocity of the slug.

37. The method of claim 31, wherein after breaking the liquid metal connection, a second liquid metal connection and a slug coupling is established between the second contact and a third contact.

38. The method of claim 37, further comprising breaking the second liquid metal connection and moving the slug by application of a second electric potential with a polarity opposite the first electric potential, said second electric potential actuating the piezoelectric element so that a negative pressure is exerted on the membrane element thereby pulling the liquid metal and the slug to re-establish the liquid metal connection between the first contact and the second contact and break the second liquid metal connection between the third contact and the second contact.

39. The method of claim 37, further comprising breaking the second liquid metal connection and moving the slug by the use of a second piezoelectric element, a second membrane element, a second electric potential, whereby the second electric potential actuates the second piezoelectric element causing the second membrane element to deflect and increase the pressure of the actuator fluid, said actuator fluid then being operable to flow and break the second liquid metal connection and move the slug.