Integrated continuous spectrum spatial light modulator

• US 20050024707A1
• Filed: 07/31/2003
• Published: 02/03/2005
• Est. Priority Date: 07/31/2003
• Status: Active Grant

• Current Assignee: Corning Incorporated
• Original Assignee: Corning Incorporated
• Inventors: Bernstein, Jonathan Jay, Dokmeci, Mehmet Remzi
• Granted Patent: US 7,187,485 B2
• Time in Patent Office: Days
• US Class Current: 359/278
• CPC Class Codes: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means
• CPC Class Codes: G02B 6/266 the optical element being an attenuator
• 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 6/3518 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 6/3566 involving bending a beam, e.g. with cantilever
• 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 6/3594 Characterised by additional functional means, e.g. means for variably attenuating or branching or means for switching differently polarized beams
• CPC Class Codes: Y10S 359/904 Micromirror

Abstract

A novel spatial light modulator system has a high fill factor MEMS array of tilting mirrors used to attenuate wavelength channels in an optical network and an interface control circuit controlling the tilting mirror array via received control signals. The control signals include definitions of the wavelength channels and desired attenuation. This control circuit may or may not be on the same chip as the mirror array. Each mirror is supported by one or more flexures, located symmetrically or asymmetrically with respect to the mirror'"'"'s center of gravity, providing single-axis or two-axis rotation. Stiffener ribs at mirror edges provide a flatter mirror. Landing electrodes held at the same potential as the mirror prevent stiction, while strain relief slots relieve stress on the mirror or flexures. Mirrors fabricated from polysilicon or metal are polished flat using a CMP technique. This SLM design is non-interferometric, therefore increased angular tilt provides increased attenuation.

Claims

1. A spatial light modulator system comprising:

a high fill factor MEMS array of tilting mirrors used to attenuate a plurality of wavelength channels in an optical network; and

an interface control circuit controlling said array of tilting mirrors said interface circuit capable of receiving and storing control signals.

2. The modulator system of claim 1 wherein said control circuit and said array of mirrors are fabricated on the same monolithic substrate.

3. The modulator system of claim 1 wherein said control circuit and said array of mirrors are not fabricated on the same monolithic substrate.

4. The modulator system of claim 1 wherein said control signals further comprise definitions for the extent of each of said plurality of wavelength channels.

5. The modulator system of claim 1 wherein the control signals further comprise a desired attenuation within each of said plurality of wavelength channels.

6. The modulator system of claim 1 wherein said MEMS array is linear.

7. The modulator system of claim 1 wherein said high fill factor is greater than or equal to 90%.

8. The modulator system of claim 1 wherein each mirror in said MEMS array of tilting mirrors further comprises a single tilting cantilever supported by two flexures.

9. The modulator system of claim 8 wherein each mirror has at least one actuation electrode.

10. The modulator system of claim 1 wherein each mirror in said MEMS array of tilting mirrors further comprises a single tilting cantilever with an asymmetric flexure resulting in 2-axis rotation.

11. The modulator system of claim 10 wherein each mirror has at least one actuation electrode.

12. The modulator system of claim 1 wherein each mirror in said MEMS array of tilting mirrors is supported by side support flexures whose rotational axis is offset from the center of gravity of the mirror.

13. The modulator system of claims 12 wherein each mirror further comprises means for providing strain relief.

14. The modulator system of claim 1 wherein each mirror in said MEMS array of tilting mirrors is supported by symmetrically located flexures whose rotational axis passes through the center of gravity of the mirror.

15. The modulator system of claims 14 wherein each mirror further comprises means for providing strain relief.

16. The modulator system of claim 1 wherein each mirror has at least one landing electrode having a same potential as said mirror.

17. The modulator system of claim 1 wherein each mirror in said MEMS array of tilting mirrors further comprises means for maintaining mirror flatness.

18. The modulator system of claim 17 where in said means for maintaining mirror flatness further comprises at least one stiffener rib located above or below the mirror plane.

19. The modulator system of claim 1 wherein each of said MEMS mirrors is fabricated of a polysilicon or metal layer.

20. The modulator system of claim 19 wherein said mirror layer is polished flat using a CMP (Chemical Mechanical Planarization) technique.