Optical switch device

• US 20030174934A1
• Filed: 03/11/2003
• Published: 09/18/2003
• Est. Priority Date: 03/15/2002
• Status: Active Grant

• Current Assignee: Nippon Telegraph and Telephone Corporation
• Original Assignee: Nippon Telegraph and Telephone Corporation
• Inventors: Ishii, Hiromu, Machida, Katsuyuki, Uenishi, Yuji, Tanabe, Yasuyuki, Shimamura, Toshishige, Urano, Masami, Kiyokura, Takanori
• Granted Patent: US 6,912,336 B2
• Time in Patent Office: Days
• US Class Current: 385/18
• CPC Class Codes: B81B 2201/042 Micromirrors, not used as optical switches
• CPC Class Codes: B81B 2203/0384 sloped profile
• CPC Class Codes: B81B 2203/04 Electrodes
• CPC Class Codes: B81B 3/0043 Increasing angular deflection
• CPC Class Codes: B81C 1/00103 Structures having a predefined profile, e.g. sloped or rounded grooves
• CPC Class Codes: B81C 1/00246 Monolithic integration, i.e. micromechanical structure and electronic processing unit are integrated on the same substrate
• CPC Class Codes: B81C 2203/0735 Post-CMOS, i.e. forming the micromechanical structure after the CMOS circuit
• 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 6/356 in an optical cross-connect device, e.g. routing and switching aspects of interconnecting different paths propagating different wavelengths to (re)configure the various input and output links switching polarized beams G02B6/3594; power equalizers G02B6/356 and G02B6/3594; path selecting means H04Q11/0001
• 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

Abstract

An optical switch device includes at least an optical switch element and driving control circuit. In the optical switch element, a fixed electrode portion is arranged, via a dielectric layer, on a semiconductor substrate on which an integrated circuit is formed. A mirror structure has a plate-shaped movable portion arranged above the fixed electrode portion while opposing the fixed electrode portion. A reflecting portion is formed at least at part of the movable portion to reflect light. A support member is fixed around the fixed electrode portion on the semiconductor substrate via a dielectric layer and supports the mirror structure. The driving control circuit is incorporated in the integrated circuit to drive the optical switch element by applying a predetermined potential to the movable portion and fixed electrode portion.

Claims

1. An optical switch device comprising at least:

an optical switch element constituted by

a fixed electrode portion arranged, via a dielectric layer, on a semiconductor substrate on which an integrated circuit is formed,

a mirror structure having a plate-shaped movable portion arranged above said fixed electrode portion while opposing said fixed electrode portion,

a reflecting portion which is formed at least at part of said movable portion to reflect light, and

a support member which is fixed around said fixed electrode portion on the semiconductor substrate via a dielectric layer and supports said mirror structure; and

a driving control circuit which is incorporated in the integrated circuit to drive said optical switch element by applying a predetermined potential to said movable portion and said fixed electrode portion.

2. A device according to claim 1, wherein said support member is formed from a plurality of structures stacked.

3. A device according to claim 2, wherein

said support member is formed from a first structure formed on the semiconductor substrate via the dielectric layer and a second structure stacked on the first structure, and

said fixed electrode portion is formed to be lower than said support member at least by a thickness of the second structure.

4. A device according to claim 2, wherein

said support member is formed from a first structure formed on the semiconductor substrate via the dielectric layer, a second structure stacked on the first structure, and a third structure stacked on the second structure, and

said fixed electrode portion includes a fourth structure formed on the semiconductor substrate via the dielectric layer and having the same thickness as that of the first structure and a fifth structure stacked on the fourth structure and having the same thickness as that of the second structure and is formed to be lower than said support member at least by a thickness of the third structure.

5. A device according to claim 4, wherein said fixed electrode portion is tapered toward a central portion of said movable portion as a distance to said mirror structure decreases.

6. A device according to claim 1, wherein said movable portion has a movable electrode.

7. A device according to claim 1, further comprising discharge means for removing charges generated in said movable portion.

8. A device according to claim 1, wherein a plurality of optical switch elements are arrayed in a matrix on the semiconductor substrate.

9. A device according to claim 1, wherein

said fixed electrode portion is formed from a plurality of electrodes which are arranged symmetrically with respect to a normal to a surface of the semiconductor substrate, which passes through a central portion of said movable portion, and

an outer side surface of each of the electrodes on an opposite side of the normal is formed to incline toward the central portion of said movable portion.