Silicon bulk-micromachined electromagnetic fiber-optics bypass microswitch

• US 6,556,737 B1
• Filed: 11/02/2000
• Issued: 04/29/2003
• Est. Priority Date: 08/02/1999
• Status: Expired due to Term

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Integrated Micromachines, Inc. (Advantest Corporation)
• Inventors: Tang, Weilong, Temesvary, Viktoria, Burns, Brent E., Miu, Denny K.
• Primary Examiner(s): Bovernick, Rodney
• Assistant Examiner(s): PAK, SUNG H
• Application Number:
  US09/705,416
• Time in Patent Office: 908 Days
• Field of Search: 385/15, 385/16, 385/18, 359/196, 359/198, 359/213, 359/224
• US Class Current: 385/16
• CPC Class Codes: B81B 2201/047 Optical MEMS not provided for in B81B2201/042 - B81B2201/045
• CPC Class Codes: B81C 1/00182 Arrangements of deformable or non-deformable structures, e.g. membrane and cavity for use in a transducer
• CPC Class Codes: B81C 2201/0133 Wet etching
• CPC Class Codes: B81C 2201/014 by depositing an etch stop layer, e.g. silicon nitride, silicon oxide, metal
• CPC Class Codes: G02B 26/0833 the reflecting element being a micromechanical device, e.g. a MEMS mirror, DMD G02B26/0825 takes precedence; micromechanical devices in general B81B
• 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 6/3572 Magnetic force magnetic forces controlling reflecting elements in general G02B26/085; magneto-optic devices G02F1/09
• 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

Abstract

A fiber-optic microswitch is disclosed that includes a flexible mirror positioning structure including an outer fixed frame, a movable platform upon which a mirror is formed, and two or more resilient support members (e.g., monocrystalline silicon springs or torsion beams) connecting the movable platform to the fixed frame. Stationary fibers are mounted over the mirror. An electromagnetic drive mechanism is provided for positioning the movable platform relative to the fixed frame. The electromagnetic drive mechanism includes one or more coils formed on a drive substrate mounted under the monocrystalline structure, and one or more pole pieces that are mounted on the movable platform. Currents are selectively applied to the coils to generate attractive electromagnetic forces that pull the pole pieces, thereby causing the movable platform to move (e.g., tilt) relative to the fixed frame, thereby selectively directing light from one fiber to another. Various monocrystalline structures are disclosed.

Claims

1. A fiber-optic micro-switch comprising:

a monocrystalline structure including a fixed outer frame, a movable platform having a mirror and a first pole piece formed thereon, and a resilient support structure connected between the fixed frame and the movable platform;

a drive structure connected to the fixed frame of the mirror structure and including a first electromagnetic coil located adjacent to the first pole piece; and

a plurality of optical fibers connected to the fixed frame of the mirror structure such that ends of the optical fibers are directed toward the mirror.

2. The fiber-optic micro-switch according to claim 1, wherein the mirror comprises a metal layer formed on the movable platform.

3. The fiber-optic micro-switch according to claim 1, wherein the first pole piece comprises electromagnetic material formed on a lower surface of the movable platform.

4. The fiber-optic micro-switch according to claim 1, wherein the first electromagnetic coil comprises a conductive material formed in a spiral shape on an upper surface of a drive substrate.

5. The fiber-optic micro-switch according to claim 1,

wherein the movable platform of the monocrystalline structure comprises a square pad having an upper surface, a lower surface, and four corners,

wherein the mirror is formed on the upper surface of the movable platform,

wherein the first pole piece is formed on the lower surface of the movable platform, and

wherein the resilient support structure comprises four serpentine silicon springs connecting the four corners of the movable platform to the fixed outer frame.

6. The fiber-optic micro-switch according to claim 5,

wherein the plurality of optical fibers include first, second, and third optical fibers fixedly connected to the fixed outer frame such that ends of the first, second, and third optical fibers are located adjacent to the mirror;

wherein when a first control signal is applied to the first electromagnetic coil, an electromagnetic force is generated that pulls the first pole piece, thereby tilting the movable platform into a first position in which the mirror reflects light transmitted through the first optical fiber to the second optical fiber, and

wherein when the first control signal is terminated, the movable platform is moved into a second position in which the mirror reflects light transmitted through the first optical fiber to the third optical fiber.

7. The fiber-optic micro-switch according to claim 6,

wherein the plurality of optical fibers further include a fourth optical fiber, and

wherein when the movable platform is in the first position, the mirror reflects light transmitted through the fourth optical fiber to the third optical fiber.

8. The fiber-optic micro-switch according to claim 6,

wherein the first pole piece is located adjacent to a first edge of the movable platform,

wherein the monocrystalline structure further includes a second pole piece formed on the movable platform and located adjacent to a second edge of the movable platform,

wherein the drive structure further includes a second electromagnetic coil located under the second pole piece.

9. The fiber-optic micro-switch according to claim 8,

wherein the plurality of optical fibers include first, second, and third optical fibers fixedly connected to the fixed outer frame such that ends of the first, second, and third optical fibers are located adjacent to the mirror;

wherein when a first control signal is applied to the first electromagnetic coil, a first electromagnetic force is generated that pulls the first pole piece, thereby tilting the movable platform into a first position in which the mirror reflects light transmitted through the first optical fiber to the second optical fiber, and

wherein when a second control signal is applied to the second electromagnetic coil, a second electromagnetic force is generated that pulls the second pole piece, thereby tilting the movable platform into a second position in which the mirror reflects light transmitted through the first optical fiber to the third optical fiber.

10. The fiber-optic micro-switch according to claim 9,

wherein the plurality of optical fibers further include a fourth optical fiber, and

wherein when the movable platform is in the first position, the mirror reflects light transmitted through the fourth optical fiber to the third optical fiber.

11. A fiber-optics micro-switch comprising:

a base structure including an outer frame, a movable platform having a mirror formed thereon, and a resilient support member connecting the outer frame to the movable platform;

an electromagnetic motor including a fixed portion mounted adjacent the movable platform and a movable portion mounted on the movable platform; and

first, second, and third optical fibers fixedly connected to the outer frame such that ends of the first, second, and third optical fibers are located adjacent to the mirror;

wherein when the electromagnetic motor exerts a first driving force on the movable platform, the movable platform is positioned such that the mirror reflects light from the first optical fiber to the second optical fiber, and

wherein when the electromagnetic motor exerts a second driving force on the movable platform, the movable platform is positioned such that the mirror reflects light from the first optical fiber to the third optical fiber.

12. A fiber-optics micro-switch comprising:

a base structure formed from a monocrystalline silicon wafer and including an outer frame, a movable platform having a mirror formed thereon, and a resilient support member connecting the outer frame to the movable platform;

first, second, and third optical fibers fixedly connected to the outer frame such that ends of the first, second, and third optical fibers are located adjacent to the mirror; and

means for moving the movable platform relative to the outer frame such that when the movable platform is in a first position, the mirror reflects light emitted from the first optical fiber to the second optical fiber, and when the movable platform is in a second position, the mirror reflects light emitted from the first optical fiber to the third optical fiber.