Monolithic waveguide/MEMS switch

• US 20040156580A1
• Filed: 12/24/2003
• Published: 08/12/2004
• Est. Priority Date: 02/22/2002
• Status: Active Grant

• Current Assignee: RPX Corporation
• Original Assignee: Lucent Technologies, Inc. (Nokia Corporation)
• Inventors: Fuchs, Dan T., Chan, Ho Bun, Stuart, Howard Roy, Baumann, Frieder Heinrich
• Granted Patent: US 7,149,378 B2
• Time in Patent Office: Days
• US Class Current: 385/16
• CPC Class Codes: G02B 2006/12104 Mirror; Reflectors or the like
• CPC Class Codes: G02B 2006/12145 Switch
• CPC Class Codes: G02B 2006/12147 Coupler
• CPC Class Codes: G02B 2006/12159 Interferometer
• CPC Class Codes: G02B 6/12007 forming wavelength selective elements, e.g. multiplexer, demultiplexer
• CPC Class Codes: G02B 6/12019 characterised by the optical interconnection to or from the AWG devices, e.g. integration or coupling with lasers or photodiodes coupling integrated waveguide to fibre G02B6/30, to optoelectronic element G02B6/42; monolithic integration of integrated waveguides with other optical elements G02B6/12004
• CPC Class Codes: G02B 6/122 Basic optical elements, e.g. light-guiding paths
• CPC Class Codes: G02B 6/2861 using fibre optic delay lines and optical elements associated with them, e.g. for use in signal processing, e.g. filtering delay lines in general H03H, H01P9/00; optical computing devices G06E
• CPC Class Codes: G02B 6/29349 Michelson or Michelson/Gires-Tournois configuration, i.e. based on splitting and interferometrically combining relatively delayed signals at a single beamsplitter
• CPC Class Codes: G02B 6/29352 in a light guide
• CPC Class Codes: G02B 6/29395 configurable, e.g. tunable or reconfigurable switching G02B6/35
• CPC Class Codes: G02B 6/3516 the reflective optical element moving along the beam path, e.g. controllable diffractive effects using multiple micromirrors within the beam
• CPC Class Codes: G02B 6/3546 NxM switch, i.e. a regular array of switches elements of matrix type constellation
• CPC Class Codes: G02B 6/3548 1xN switch, i.e. one input and a selectable single output of N possible outputs
• 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
• 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 monolithic waveguide/MEMS switch is disclosed that has a waveguide portion and a MEMS mirror portion fabricated on a single substrate, such as a as a silicon-on-insulator wafer. The monolithic waveguide/MEMS switch adjusts the phase of an optical signal by varying the position of one or more moveable mirrors. The mirror portion includes a mirror having a reflective surface that is attached to at least one MEMS actuator to achieve in-plane motion of the mirror (moves parallel to a plane of said at least one waveguide). In one implementation, the MEMS actuator is embodied as a known comb drive actuator. The phase adjustment techniques of the present invention may be employed in various optical devices, including wavelength selective optical switches that support multiple optical channels.

Claims

1. An optical device on a single substrate, comprising:

a waveguide portion having at least one waveguide; and

a mirror portion fabricated on said single substrate with said waveguide portion, wherein said mirror portion includes at least one mirror that is adapted to move parallel to a plane of said at least one waveguide.

2. The optical device according to claim 1, wherein said single substrate is a silicon-on-insulator wafer.

3. The optical device according to claim 1, wherein said at least one mirror is controlled by a micromachine control element that positions said mirror in a desired position along an optical path.

4. The optical device according to claim 1, wherein said mirror is positioned at an end of said at least one waveguide.

5. The optical device according to claim 1, wherein said mirror is fabricated using a reflective coating.

6. The optical device according to claim 1, wherein said waveguide portion is coated with an antireflective coating.

7. The optical device according to claim 1, wherein an adjustment to a position of said mirror adjusts a phase of an optical signal.

8. The optical device according to claim 1, wherein said mirror portion comprises a stationary portion having an actuator rigidly connected to a substrate and a moveable portion comprising a moveable mirror, a shaft rigidly connected to said moveable mirror and a moveable portion of the actuator rigidly connected to the shaft.

9. A method for fabricating an optical device on a single substrate, comprising the steps of:

forming at least one waveguide in a waveguide portion of said single substrate; and

forming a mirror portion on said single substrate with said waveguide portion, wherein said mirror portion includes at least one mirror that is adapted to move parallel to a plane of said at least one waveguide.

10. The method according to claim 9, wherein said single substrate is a silicon-on-insulator wafer.

11. The method according to claim 9, wherein said step of forming a mirror portion further comprises the step of forming a micromachine control element that positions said mirror in a desired position.

12. The method according to claim 9, wherein said step of forming a mirror portion further comprises the step of etching said mirror portion in silicon.

13. The method according to claim 9, wherein said mirror is positioned at an end of said at least one waveguide.

14. The method according to claim 9, wherein said step of forming a mirror portion further comprises the step of placing a reflective coating.

15. The method according to claim 9, wherein said step of forming at least one waveguide further comprises the step of coating said waveguide portion with an antireflective coating.

16. The method according to claim 9, wherein said step of forming at least one waveguide further comprises the step of etching said waveguide portion in silicon.

17. The method according to claim 9, further comprising the step of cutting and polishing said optical device for fiber coupling.

18. The method according to claim 9, further comprising the step of mechanically releasing said optical device by etching the sacrificial oxide in a buffered oxide etch (BOE) and subsequently drying it using a critical point drying process.

19. The method according to claim 9, wherein said mirror portion comprises a stationary portion having an actuator rigidly connected to a substrate and a moveable portion comprising a moveable mirror, a shaft rigidly connected to said moveable mirror and a moveable portion of the actuator rigidly connected to the shaft.

20. An optical device on a single substrate, comprising:

a waveguide portion having at least one waveguide; and

a mirror portion fabricated on said single substrate with said waveguide portion, wherein said mirror portion includes at least one mirror that is adapted to move parallel to a plane of said at least one waveguide; and

a micromachine control element that positions said mirror in a desired position along an optical path.

21. The optical device according to claim 20, wherein an adjustment to a position of said mirror adjusts a phase of an optical signal.