Variable blazed grating

• US 6,445,502 B1
• Filed: 02/02/2001
• Issued: 09/03/2002
• Est. Priority Date: 02/02/2001
• Status: Expired due to Fees

• Current Assignee: Cheetah Omni LLC
• Original Assignee: Celeste Optics, Inc.
• Inventors: Islam, Mohammed N., Kuditcher, Amos
• Primary Examiner(s): Spyrou, Cassandra
• Assistant Examiner(s): Juba, Jr., John
• Application Number:
  US09/776,051
• Time in Patent Office: 578 Days
• Field of Search: 359/290, 359/291, 359/292, 359/295, 359/571, 359/572, 359/573, 359/900
• US Class Current: 359/571
• CPC Class Codes: G02B 26/0808 by means of one or more diffracting elements
• CPC Class Codes: G02B 6/12009 comprising arrayed waveguide grating [AWG] devices, i.e. with a phased array of waveguides
• CPC Class Codes: G02B 6/2932 comprising a directional router, e.g. directional coupler, circulator
• CPC Class Codes: G02B 6/29322 Diffractive elements of the tunable type G02B6/02195 takes precedence; optical modulation devices based on a change of the optical properties of the medium G02F1/00
• CPC Class Codes: Y10S 359/90 Methods

Abstract

In one aspect of the invention, an apparatus operable to provide optical signal processing includes an inner conductive layer including an at least substantially conductive material and a plurality of at least partially reflective mirror strips disposed outwardly from the inner conductive layer and operable to receive an input optical signal, wherein none of the plurality of strips has a width greater than 40 microns. At least some of the strips are operable to undergo a partial rotation in response to a control signal, the partial rotation resulting in a diffraction of the input optical signal wherein a majority of the diffracted input signal is communicated in one direction.

Claims

1. An apparatus operable to provide optical signal processing, the apparatus comprising:

an inner conductive layer comprising an at least substantially conductive material; and

a plurality of at least partially reflective mirror strips disposed outwardly from the inner conductive layer and operable to receive an input optical signal, wherein none of the plurality of strips has a width greater than 40 microns and wherein at least some of the strips are operable to undergo a partial rotation in response to a control signal, the partial rotation resulting in a diffraction of the input optical signal wherein a majority of the diffracted input signal is communicated in one direction;

wherein the control signal comprises a voltage operable to create one of a plurality of selectable non-zero voltage differentials between the mirror strips and the inner conductive layer to result in one of a plurality of selectable angles of rotation of the mirror strips, and a corresponding one of a plurality of selectable attenuations of the input signal.

2. The apparatus of claim 1, wherein none of the plurality of strips comprises a width that is greater than 20 microns.

3. The apparatus of claim 1, wherein each of the plurality of mirror strips comprises an at least substantially conductive material.

4. The apparatus of claim 1, wherein the inner conductive layer comprises:

a plurality of electrically coupled first conductors, each associated with a separate mirror strip and disposed approximately inwardly from a first edge of the associated strip; and

wherein the inner conductive layer is operable to facilitate a first voltage differential between the inner conductive layer and at least the first edges of the associated mirror strips to create an electrostatic force tending to rotate the first edges of the mirror strips toward the associated first conductor.

5. The apparatus of claim 4, wherein the inner conductive layer further comprises a plurality of electrically coupled second conductors, each associated with alternate ones of the mirror strips and disposed inwardly from at least a second edge opposite the first edge of the alternate mirror strips, wherein the second conductors operate to facilitate a voltage differential between the second conductors and the associated alternate mirror strips to create an electrostatic force tending to move the alternate strips inwardly relative to strips adjacent to the alternate mirror strips.

6. The apparatus of claim 1, wherein the inner conductive layer comprises a continuous layer of an at least substantially conductive material disposed inwardly from the plurality of mirror strips.

7. The apparatus of claim 1, wherein each of the mirror strips comprises:

a layer of electrically insulating material;

a first portion of at least partially reflective and at least substantially conductive material disposed outwardly from a first edge of the insulating layer;

a second portion of at least partially reflective material disposed outwardly from the insulating layer and separated from the first portion by a channel;

wherein a voltage differential between the first portion and the inner conductive layer operates to create an electrostatic force between the first portion and the inner conductive layer tending to rotate the first portion toward the inner conductive layer.

8. The apparatus of claim 7, wherein the second portion is electrically coupled to the inner conductive layer.

9. The apparatus of claim 1, wherein each of the mirror strips comprises:

an inner surface facing the inner conductive layer; and

an outer surface joining the inner surface at an angle, wherein the outer surfaces of two adjacent strips are each operable to receive a portion of an optical input signal and to reflect the received portion at an output angle; and

wherein alternate ones of the mirror strips are operable to move relative to adjacent mirror strips by a selected distance to create a desired phase difference between the reflected beam portions.

10. The apparatus of claim 1, wherein the rotation of the strips creates a periodicity of the apparatus wherein an angle of diffraction of the diffracted signal portions is approximately equal to an angle of incidence of the input optical signal.

11. The apparatus of claim 1, wherein the rotation of the strips determines the diffraction efficiency of the apparatus.

12. The apparatus of claim 1, wherein the majority of diffracted portions of the input signal combine to form an output that is attenuated relative to the input signal by an amount determined at least in part by the amount of partial rotation of the strips.

13. The apparatus of claim 1, wherein the partial rotation causes a majority of diffracted portions of the input signal to constructively interfere with one another after the strips have been partially rotated to result in an output port switching from receiving approximately no signal to receiving the combination of constructively interfering diffracted signal portions.

14. A method of processing optical signals using a blazed grating, the method comprising:

receiving an optical signal at a plurality of at least partially reflective mirror strips residing in a first position outwardly from an inner conductive layer, wherein none of the plurality of strips has a width of more than 40 microns; and

rotating the mirror strips by an angle THETA from the first position in response to a control signal to create a plurality of diffracted signal portions, the majority of the diffracted signal portions being diffracted in one direction;

wherein the control signal comprises a voltage operable to create one of a plurality of selectable non-zero voltage differentials between the mirror strips and the inner conductive layer to result in one of a plurality of selectable angles of rotation of the mirror strips, and a corresponding one of a plurality of selectable attenuations of the input signal.

15. The method of claim 14, wherein none of the plurality of strips comprises a width that is greater than 20 microns.

16. The method of claim 14, wherein each of the plurality of mirror strips comprises an at least substantially conductive material.

17. The method of claim 14, wherein rotating the mirror strips comprises applying a voltage differential between at least a first edge of each mirror strip and an inner conductive layer disposed inwardly from the first edges of the mirror strips, the voltage differential creating an electrostatic force tending to rotate the first edge toward the inner conductive layer.

18. The method of claim 17, wherein the inner conductive layer comprises a plurality of electrically coupled first conductors, each associated with a separate mirror strip and disposed approximately inwardly from a first edge of the associated strip.

19. The method of claim 18, wherein the inner conductive layer further comprises a plurality of electrically coupled second conductors, each associated with alternate ones of the mirror strips and disposed inwardly from at least a second edge opposite the first edge of the alternate mirror strips, wherein the second conductors operate to facilitate a voltage differential between the second conductors and the associated alternate mirror strips to create an electrostatic force tending to move the alternate strips inwardly relative to strips adjacent to the alternate mirror strips.

20. The method of claim 17, wherein the inner conductive layer comprises a continuous layer of an at least substantially conductive material disposed inwardly from the plurality of mirror strips.

21. The method of claim 17, wherein each of the mirror strips comprises:

an inner surface facing the inner conductive layer; and

an outer surface joining the inner surface at an angle, wherein the outer surfaces of two adjacent strips are each operable to receive a portion of an optical input signal and to reflect the received portion at an output angle; and

wherein alternate ones of the mirror strips are operable to move relative to adjacent mirror strips by a selected distance to create a desired phase difference between the reflected beam portions.

22. The method of claim 17, wherein each of the mirror strips comprises:

a layer of electrically insulating material;

a first portion of at least partially reflective and at least substantially conductive material disposed outwardly from a first edge of the insulating layer;

a second portion of at least partially reflective material disposed outwardly from the insulating layer and separated from the first portion by a channel;

wherein a voltage differential between the first portion and the inner conductive layer operates to create an electrostatic force between the first portion and the inner conductive layer tending to rotate the first portion toward the inner conductive layer.

23. The method of claim 22, wherein the second portion is electrically coupled to the inner conductive layer.

24. The method of claim 14, wherein the angle THETA results in a periodicity of the apparatus wherein an angle of diffraction of the diffracted signal portions is approximately equal to an angle of incidence of the input optical signal.

25. The method of claim 14, wherein a phase difference between the signal portions diffracted from adjacent mirror strips in one direction and the diffraction efficiency of the apparatus is determined at least in part by the angle THETA.

26. The method of claim 14, wherein the majority of diffracted portions of the input signal combine to form an output that is attenuated relative to the input signal by an amount determined at least in part by the amount of partial rotation of the strips.

27. The method of claim 14, wherein the partial rotation causes a majority of diffracted portions of the input signal constructively interfere with one another after the strips have been partially rotated to result in an output port switching from receiving approximately no signal to receiving the combination of constructively interfering diffracted signal portions.

28. An apparatus operable to provide optical signal processing, the apparatus comprising:

an inner conductive layer comprising an at least substantially conductive material; and

a plurality of at least partially reflective mirror strips disposed outwardly from the inner conductive layer and operable to receive an input optical signal, wherein at least some of the strips are operable to undergo a partial rotation of more than two degrees in response to a control signal, the partial rotation resulting in a diffraction of the input optical signal wherein a majority of the diffracted input signal is communicated in one direction;

wherein the control signal comprises a voltage operable to create one of a plurality of selectable non-zero voltage differentials between the mirror strips and the inner conductive layer to result in one of a plurality of selectable angles of rotation of the mirror strips, and a corresponding one of a plurality of selectable attenuations of the input signal.

29. The apparatus of claim 28, wherein none of the plurality of strips comprises a width greater than 40 microns.

30. The apparatus of claim 28, wherein each of the plurality of strips comprises a width less than 20 microns.

31. A method of processing optical signals using a blazed grating, the method comprising:

receiving an optical signal at a plurality of at least partially reflective mirror strips residing in a first position and disposed outwardly from an inner conductive layer; and

rotating the mirror from the first position in response to a control signal to create a plurality of diffracted signal portions, the majority of the diffracted signal portions being diffracted in one direction, tie strips having a maximum rotation angle that is greater than two degrees;

wherein the control signal comprises a voltage operable to create one of a plurality of selectable non-zero voltage differentials between the mirror strips and the inner conductive layer to result in one of a plurality of selectable angles of rotation of the mirror strips, and a corresponding one of a plurality of selectable attenuations of the input signal.

32. The method of claim 31, wherein none of the plurality of strips has a width greater than 40 microns.

33. The method of claim 31, wherein none of the plurality of strips has a width greater than 20 microns.

38. The method of claim 32, wherein the second portion is electrically coupled to the inner conductive layer.

34. An apparatus operable to provide optical signal processing, the apparatus comprising:

an inner conductive layer comprising an at least substantially conductive material; and

a plurality of at least partially reflective mirror strips disposed outwardly from the inner conductive layer and operable to receive an input optical signal, wherein none of the plurality of strips has a width greater than 40 microns and wherein at least some of the strips are operable to undergo a partial rotation in response to a control signal, the partial rotation resulting in a diffraction of the input optical signal wherein a majority of the diffracted input signal is communicated in one direction;

wherein each of the mirror strips comprises;

a layer of electrically insulating material;

a first portion of at least partially reflective and at least substantially conductive material disposed outwardly from a first edge of the insulating layer;

a second portion of at least partially reflective material disposed outwardly from the insulating layer and separated from the first portion by a channel;

wherein a voltage differential between the first portion and the inner conductive layer operates to create an electrostatic force between the first portion and the inner conductive layer tending to rotate the first portion toward the inner conductive layer.

35. The apparatus of claim 34, wherein the second portion is electrically coupled to the inner conductive layer.

36. An apparatus operable to provide optical signal processing, the apparatus comprising:

an inner conductive layer comprising an at least substantially conductive material; and

a plurality of at least partially reflective mirror strips disposed outwardly from the inner conductive layer and operable to receive an input optical signal, wherein none of the plurality of strips has a width greater than 40 microns and wherein at least some of the strips are operable to undergo a partial rotation in response to a control signal, the partial rotation resulting in a diffraction of the input optical signal wherein a majority of the diffracted input signal is communicated in one direction;

wherein each of the mirror strips comprises;

an inner surface facing the inner conductive layer; and

an outer surface joining the inner surface at an angle, wherein the outer surfaces of two adjacent strips are each operable to receive a portion of an optical input signal and to reflect the received portion at an output angle; and

wherein alternate ones of the mirror strips are operable to move relative to adjacent mirror strips by a selected distance to create a desired phase difference between the reflected beam portions.

37. A method of processing optical signals using a blazed grating, the method comprising:

receiving an optical signal at a plurality of at least partially reflective mirror strips residing in a first position, wherein none of the plurality of strips has a width of more than 40 microns; and

rotating the mirror strips by an angle THETA from the first position to create a plurality of diffracted signal portions, the majority of the diffracted signal portions being diffracted in one direction;

wherein each of the mirror strips comprises;

a layer of electrically insulating material;

a first portion of at least partially reflective and at least substantially conductive material disposed outwardly from a first edge of the insulating layer;

a second portion of at least partially reflective material disposed outwardly from the insulating layer and separated from the first portion by a channel; and

wherein a voltage differential between the first portion and the inner conductive layer operates to create an electrostatic force between the first portion and the inner conductive layer tending to rotate the first portion toward the inner conductive layer.

39. A method of processing optical signals using a blazed grating, the method comprising:

receiving an optical signal at a plurality of at least partially reflective mirror strips residing in a first position, wherein none of the plurality of strips has a width of more than 40 microns; and

rotating the mirror strips by an angle THETA from the first position to create a plurality of diffracted signal portions, the majority of the diffracted signal portions being diffracted in one direction;

wherein each of the mirror strips comprises;

an inner surface facing the inner conductive layer; and

an outer surface joining the inner surface at an angle, wherein the outer surfaces of two adjacent strips are each operable to receive a portion of an optical input signal and to reflect the received portion at an output angle; and

wherein alternate ones of the mirror strips are operable to move relative to adjacent mirror strips by a selected distance to create a desired phase difference between the reflected beam portions.