Fluid-encapsulated MEMS optical switch

• US 6,404,942 B1
• Filed: 10/19/1999
• Issued: 06/11/2002
• Est. Priority Date: 10/23/1998
• Status: Expired due to Fees

• Current Assignee: Corning Incorporated
• Original Assignee: Corning Incorporated
• Inventors: Edwards, Victoria Ann, Brophy, Christopher Philip, Chamberlain, Darol, Eid, Bernard
• Primary Examiner(s): Healy, Brian
• Assistant Examiner(s): HAHM, SARAH UH YOUNG
• Application Number:
  US09/421,765
• Time in Patent Office: 966 Days
• Field of Search: 385/16-18, 385/20-22
• 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 6/3518 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 6/357 Electrostatic force electrostatic forces controlling reflecting elements in general G02B26/0841
• CPC Class Codes: G02B 6/3572 Magnetic force magnetic forces controlling reflecting elements in general G02B26/085; magneto-optic devices G02F1/09
• CPC Class Codes: G02B 6/3576 Temperature or heat actuation thermal forces controlling reflecting elements in general G02B26/0866; thermo-optic devices G02F1/0147
• 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

A fluid encapsulated MEMS optical switch includes an optical waveguide matrix with MEMS mirrors situated in trenches located at waveguide cross-points. The trenches are filled with collimation-maintaining fluid and the mirrors are immersed therein. The collimation maintaining fluid prevents the light beam from spreading when it enters the switch cross-points. This feature enables the use of much smaller MEMS mirrors and prevents some of the typical MEMS mirror problems found in the related art. In particular, the MEMS mirror disclosed in the present invention is reduced to approximately 15 μm wide and 2 μm thick, resulting in shorter actuation distances of approximately 15 μm. This feature results in an optical switch having faster switching times.

Claims

1. An optical switch for directing a light signal, said optical switch comprising:

a plurality of input optical waveguides;

a plurality of output optical waveguides that intersect said plurality of input optical waveguides at a plurality of cross-points, the plurality of input optical waveguides and the plurality of output optical waveguides being integrally formed on a first substrate;

a plurality of trenches formed at said plurality of cross-points;

a collimation-maintaining fluid disposed in said plurality of trenches;

an array of movable switching elements, each switching element associated with a trench of said plurality of trenches for directing a light signal into an associated one of said output waveguides, said movable switching element being substantially immersed in said collimation-maintaining fluid when in a closed position; and

a second substrate connected to said first substrate for encapsulating the collimation-maintaining fluid within the plurality of trenches and for providing actuation of said array of movable switching elements.

2. The optical switch of claim 1, wherein the array of movable switching elements, the plurality of input waveguides, and the plurality of output waveguides form an N×

M non-blocking cross-bar switch, wherein N is the number of input waveguides, M is the number of output waveguides and N×

M is the number of movable switching elements.

3. The optical switch of claim 1, wherein each of the array of movable switching elements further comprises:

a mirror element connected to a plate and extending from said plate into said trench.

4. The optical switch of claim 3, further comprising a two dimensional array of electrostatic actuators disposed on the second substrate, wherein each electrostatic actuator of said array of electrostatic actuators is aligned with a corresponding movable switching element in the array of movable switching elements.

5. The optical switch of claim 4, wherein the plate attached to said moveable switch element is moved by electrostatic attraction when the electrostatic actuator is energized, causing the mirror element to be moved within the trench into an open position.

6. The optical switch of claim 4, wherein the plate is in a quiescent state when the electrostatic actuator is not energized, to thereby cause the moveable switch element to be in the closed position.