Frustrated total internal reflection-based micro-opto-electro-mechanical modulator/demodulator

• US 6,433,911 B1
• Filed: 05/19/2000
• Issued: 08/13/2002
• Est. Priority Date: 05/19/2000
• Status: Expired due to Fees

• Current Assignee: Massachusetts Institute of Technology
• Original Assignee: Massachusetts Institute of Technology
• Inventors: Chen, Dye-Zone A., Barbastathis, George
• Primary Examiner(s): Lester, Evelyn A.
• Application Number:
  US09/574,267
• Time in Patent Office: 816 Days
• Field of Search: 359/117, 359/128, 359/130, 359/179, 359/222-247, 359/252, 359/254, 359/261-263, 359/276-279, 359/291-298, 359/299, 359/300-304, 359/317, 359/320, 359/566-572, 359/589, 359/615, 359/639, 359/834, 385/10, 385/14, 385/18, 385/22, 385/37, 385/42, 385/133, 385/30, 385/7, 385/8
• US Class Current: 359/199.4
• CPC Class Codes: G02B 26/02 for controlling the intensity of light G02B26/004 takes precedence
• CPC Class Codes: G02B 6/29307 components assembled in or forming a solid transparent unitary block, e.g. for facilitating component alignment
• CPC Class Codes: G02B 6/2931 Diffractive element operating in reflection
• CPC Class Codes: G02B 6/29311 Diffractive element operating in transmission
• CPC Class Codes: G02B 6/29383 Adding and dropping
• 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 6/3522 the optical element enabling or impairing total internal reflection using evanescent coupling G02B6/3536
• 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 6/4215 the intermediate optical elements being wavelength selective optical elements, e.g. variable wavelength optical modules or wavelength lockers G02B6/4246 takes precedence

Abstract

A micro-opto-electro-mechanical systems (MOEMS) modulator based on the phenomenon of frustrated total internal reflection (FTIR). The modulator effects amplitude and phase modulation at the boundary of a waveguide. Wavelength-specific switching is achieved by spatially separating the wavelength channels by dispersing a broadband input signal into its wavelength components through a grating. In exemplary embodiments, an array of micro-fabricated actuators is used to switch or modulate wavelengths individually. Applications include wavelength and space-resolved phase and amplitude modulation of optical beams, and re-configurable add/drop switching of dense wavelength-division multiplexed (DWDM) optical communication signals.

Claims

1. A method of modulating light comprising:

providing a light beam to an optical substrate at an input region;

dispersing said light beam into distinct wavelengths within said optical substrate; and

outputting selected ones of said distinct wavelengths propagating within said optical substrate with micro-electro-mechanical actuators positioned at a region of said substrate to interact with each of said distinct wavelengths.

2. The method of claim 1 further comprising providing dispersion grating to disperse said light beam.

3. The method of claim 1, wherein said substrate comprises a first silicon wafer.

4. The method of claim 3, wherein said micro-electro-mechanical actuators are provided on a second substrate.

5. The method of claim 4, wherein said second substrate comprises a second silicon wafer that is bonded to said first silicon wafer.

6. The method of claim 1, wherein said light beam comprises a wavelength-division multiplexed signal.

7. The method of claim 1, wherein said light beam comprises white light.

8. The method of claim 7, wherein said substrate comprises fused silica.

9. The method of claim 1 further comprising modulating said selected ones of said distinct wavelengths with a digital picture.

10. The method of claim 1, wherein said light is phase, amplitude and polarization modulated in both spectrum and space.

11. A light modulator comprising:

an optical substrate having an input region for receiving a light beam;

a light dispersing element which disperses said light beam into distinct wavelengths within said optical substrate; and

micro-electro-mechanical actuators which output selected ones of said distinct wavelengths propagating within said optical substrate, said micro-electro-mechanical actuators positioned at a region of said substrate to interact with each of said distinct wavelengths.

12. A re-configurable add/drop switch for DWDM signals comprising:

an optical substrate having an input region for receiving a light beam representative of DWDM signals;

a light dispersing element which disperses said light beam into distinct wavelengths within said optical substrate; and

micro-electro-mechanical actuators which output selected ones of said distinct wavelengths propagating within said optical substrate, said micro-electro-mechanical actuators positioned at a region of said substrate to interact with each of said distinct wavelengths.