Apparatus and method for providing gain equalization

• US 7,116,862 B1
• Filed: 02/25/2005
• Issued: 10/03/2006
• Est. Priority Date: 12/22/2000
• Status: Expired due to Fees

• Current Assignee: Cheetah Omni LLC
• Original Assignee: Cheetah Omni LLC
• Inventors: Islam, Mohammed N., Kuditcher, Amos
• Primary Examiner(s): PAK, SUNG H
• Application Number:
  US11/066,635
• Time in Patent Office: 585 Days
• Field of Search: None
• US Class Current: 385/24
• 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 6/3546 NxM switch, i.e. a regular array of switches elements of matrix type constellation
• 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 6/3592 Means for removing polarization dependence of the switching means, i.e. polarization insensitive switching light guides coupling with polarization selective and adjusting means G02B6/27
• 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

Abstract

In one aspect of the invention, a gain equalizer comprises a wavelength division demultiplexer operable to separate one or more communication bands into a plurality of wavelengths and an array of phase shifter stages. Each phase shifter stage comprises a micro-electro-optic system (MEMS) device comprising a moveable mirror layer operable to receive a first copy of an input signal from a beam splitter and to reflect the first copy of the input signal for combination with a second copy of the input signal at an output to form an output signal. The moveable mirror layer is displaceable in a substantially piston-like motion to introduce a phase shift between the first and second signal copies at the output, the amplitude of the output signal varying depending on the displacement of the moveable mirror layer. The gain equalizer further comprises a wavelength division multiplexer operable to receive a plurality of phase shifted wavelengths from the second beam splitter and to multiplex at least some of the phase shifted wavelengths into an optical output signal.

Claims

1. An optical processing system, comprising:

a light pipe operable to communicate an optical signal for processing, the optical signal comprising a plurality of wavelengths;

an optical signal separator operable to receive the optical signal communicated by the light pipe;

a first beam splitter coupled to the optical signal separator and operable to divide at least a portion of the optical signal communicated by the light pipe into at least a first part and a second part wherein the first part of the optical signal and the second part of the optical input signal comprise unequal amplitudes;

a micro-electro-optic system (MEMS) device operable to receive at least the first part of the optical signal, the MEMS device comprising a moveable mirror operable to receive the portion of first part of the optical signal and to reflect the portion of the first part to form a MEMS output signal having an amplitude, the amplitude of the MEMS output signal capable of being varied depending on the movement of the moveable mirror; and

an optical reflector operable to receive at least some of the MEMS output signal and to communicate the MEMS output signal to an output interface.

2. The optical processing system of claim 1, wherein the MEMS device comprises:

an inner conductive layer disposed inwardly from the moveable mirror and forming a space between the moveable mirror and the inner conductive layer;

wherein the moveable mirror comprises an at least substantially conductive structure operable to move relative to the inner conductive layer in response to a voltage difference between the moveable mirror and the inner conductive layer.

3. The optical processing system of claim 2, wherein at least a portion of the inner conductive layer is substantially non-reflecting.

4. The optical processing system of claim 3, wherein the substantially non-reflecting layer is selected from the group consisting of a semiconductor substrate, a metal, and a layer of doped polysilicon.

5. The optical processing system of claim 3, wherein the substantially non-reflecting layer comprises multiple layers of one or more materials.

6. The optical processing system of claim 1, wherein the first beam splitter is selected from the group consisting of a substrate having at least one layer of a dielectric coating, a partially silvered mirror, and a fiber coupler.

7. The optical processing system of claim 1, wherein the optical signal separator comprises a wavelength division demultiplexer.

8. The optical processing system of claim 1, wherein the optical signal separator comprises a beam splitter with one or more dielectric layers.

9. The optical processing system of claim 1, wherein the optical reflector comprises one or more mirrors.

10. The optical processing system of claim 1, further comprising one or more reflective surfaces to communicate the optical signal to the MEMS device.

11. The optical processing system of claim 1, further comprising a moveable reflector operable to receive the portion of first part of the optical input signal and to reflect the portion of the first part to the moveable mirror of the MEMS device.

12. The optical processing system of claim 1, further comprising a moveable reflector operable to receive the portion of first part of the optical signal from the moveable mirror of the MEMS device and to reflect the portion of the first part to the optical reflector.

13. A method of processing multiple wavelengths of light, the method comprising:

communicating an optical signal for processing, the optical signal comprising a plurality of wavelengths;

separating the optical signal communicated for processing into at least a first portion of optical signal wavelengths and a second portion optical signal wavelengths;

dividing at least a portion of the optical signal communicated for processing into at least a first part and a second part, wherein the first part comprises an amplitude that is different than an amplitude of the second part;

receiving at least the first portion of optical signal wavelengths at a moveable mirror of a micro-electro-optic system (MEMS) device;

reflecting the first portion of optical signal wavelengths from the moveable mirror to form at least one MEMS output signal having an amplitude, the amplitude of the MEMS output signal capable of being changed by moving the moveable mirror; and

communicating the at least one MEMS output signal to an output interface.

14. The method of claim 13, wherein the MEMS device comprises:

an inner conductive layer disposed inwardly from the moveable mirror and forming a space between the moveable mirror and the inner conductive layer;

wherein the moveable mirror is operable to move relative to the inner conductive layer in response to a voltage difference between the moveable mirror and the inner conductive layer.

15. The method of claim 14, wherein the inner conductive layer is substantially non-reflecting.

16. The method of claim 15, further receiving at least the first portion of optical signal wavelengths at a moveable reflector and reflecting the first portion to the moveable mirror of the MEMS device.

17. The method of claim 15, further receiving at least the first portion of optical signal wavelengths from the moveable mirror of the MEMS device at a moveable reflector and reflecting the first portion to the output interface.

18. An optical processing system, comprising:

a light pipe operable to communicate an optical signal for processing, the optical signal comprising a plurality of wavelengths;

an optical signal separator operable to receive the optical signal communicated by the light pipe;

a first beam splitter operable to divide at least a portion of the optical signal communicated by the light pipe into at least a first part and a second part wherein the first part of the optical signal and the second part of the optical input signal comprise unequal amplitudes;

a micro-electro-optic system (MEMS) device operable to receive at least the first part of the optical signal, the MEMS device comprising;

a moveable mirror operable to receive the portion of first part of the optical input signal and to reflect the portion of the first part to form a MEMS output signal having an amplitude, the amplitude of the MEMS output signal capable of being varied depending on the movement of the moveable mirror; and

an inner conductive layer disposed inwardly from the moveable mirror and forming a space between the moveable mirror and the inner conductive layer, at least a portion of the inner conductive layer comprising a metal and is substantially non-reflecting, wherein the moveable mirror comprises an at least substantially conductive structure operable to move relative to the inner conductive layer in response to a voltage difference between the moveable mirror and the inner conductive layer; and

an optical reflector operable to receive at least some of the MEMS output signal and to communicate the MEMS output signal to an output interface.

19. The optical processing system of claim 18, further comprising a moveable reflector operable to receive the portion of first part of the optical input signal and to reflect the portion of the first part to the moveable mirror of the MEMS device.

20. The optical processing system of claim 18, further comprising a moveable reflector operable to receive the portion of first part of the optical input signal from the moveable mirror of the MEMS device and to reflect the portion of the first part to the optical reflector.