Optical waveguide structure with partially overlapping loops in direction dependent material

1. An optical waveguide structure comprising:

a main nonlinear optical waveguide, wherein a first-wavelength light and a second-wavelength light travel in the main nonlinear optical waveguide;

a first extension optical waveguide;

a secondary optical waveguide;

a first wavelength-selective coupler that optically couples the main nonlinear optical waveguide and the first extension optical waveguide to each other such that the first-wavelength light is coupled from the main nonlinear optical waveguide to the first extension optical waveguide,

and that optically couples the main nonlinear optical waveguide and the secondary optical waveguide to each other such that the second-wavelength light is coupled from the main nonlinear optical waveguide to the secondary optical waveguide;

and

a second wavelength-selective coupler that optically couples the main nonlinear optical waveguide and the first extension optical waveguide to each other such that the first-wavelength light is coupled from the first extension optical waveguide to the main nonlinear optical waveguide,

and that optically couples the main nonlinear optical waveguide and the secondary optical waveguide to each other such that the second-wavelength light is coupled from the secondary optical waveguide to the main nonlinear optical waveguide.

2. The optical waveguide structure of claim 1 further comprising:

a second extension optical waveguide;

a third wavelength-selective coupler that optically couples the secondary optical waveguide and the second extension optical waveguide to each other such that the second-wavelength light is coupled from the secondary optical waveguide to the second extension optical waveguide; and

a fourth wavelength-selective coupler that optically couples the secondary optical waveguide and the second extension optical waveguide to each other such that the second-wavelength light is coupled from the second extension optical waveguide to the secondary optical waveguide.

3. The optical waveguide structure of claim 2 further comprising:

a third extension optical waveguide;

wherein the third wavelength-selective coupler optically couples the secondary optical waveguide and the third extension optical waveguide to each other such that a third-wavelength light is coupled from the secondary optical waveguide to the third extension optical waveguide and the second-wavelength light is not coupled into the third extension optical waveguide; and

wherein the fourth wavelength-selective coupler optically couples the secondary optical waveguide and the third extension optical waveguide to each other such that the third-wavelength light is coupled from the third extension optical waveguide to the secondary optical waveguide.

4. The optical waveguide structure of claim 3 , wherein the first-wavelength light travels in a first loop through a main segment within the main nonlinear optical waveguide, through and a first extension segment, and through the first wavelength-selective coupler and the second wavelength-selective coupler, in which the first loop has a first length;

wherein the second-wavelength light travels in a second loop through a secondary segment in the secondary optical waveguide, through the second extension optical waveguide, through the first wavelength-selective coupler and the second wavelength-selective coupler, through the third wavelength-selective coupler and the fourth wavelength-selective coupler, and through the main segment in the main nonlinear optical waveguide, in which the second loop has a second length for the second-wavelength light; and

wherein the third-wavelength light travels in a third loop through the secondary segment in the secondary optical waveguide, through the third extension optical waveguide, through the first wavelength-selective coupler and the second wavelength-selective coupler, through the third wavelength-selective coupler and the fourth wavelength-selective coupler, and through the main segment in the main nonlinear optical waveguide, in which the third loop as a third length for the third-wavelength light.

5. The optical waveguide structure of claim 4 further comprising:

a phase shifter located adjacent to a portion of the third extension optical waveguide, wherein the phase shifter applies an activation such that a phase shifts in the third-wavelength light to achieve a resonance condition for the third-wavelength light.

6. The optical waveguide structure of claim 3 , wherein the first-wavelength light is a pump light, the second-wavelength light is a signal light, and the third-wavelength light is an idler light; and wherein an intensity of the first-wavelength light is greater than an intensity of the second-wavelength light and is greater than an intensity of the third-wavelength light.

7. The optical waveguide structure of claim 3 , wherein the third extension optical waveguide is comprised of at least one of an electro-optical material, a nonlinear optical material or a non-nonlinear optical material.

8. The optical waveguide structure of claim 3 , wherein the third extension optical waveguide is comprised of an electro-optical material.

9. The optical waveguide structure of claim 3 further comprising:

a set of output optical waveguides that outputs output light out of at least one of the first extension optical waveguide, the second extension optical waveguide, or the third extension optical waveguide.

10. The optical waveguide structure of claim 3 further comprising:

a set of input optical waveguides that inputs input light into at least one of the first extension optical waveguide, the second extension optical waveguide, or the third extension optical waveguide.

11. The optical waveguide structure of claim 3 further comprising:

a phase shifter located adjacent to a portion of the third extension optical waveguide, wherein the phase shifter applies an activation such that a phase shifts in the third-wavelength light to achieve a round-trip phase matching condition for a nonlinear optical process involving the third-wavelength light.

12. The optical waveguide structure of claim 3 further comprising:

a phase shifter located adjacent to a portion of the third extension optical waveguide, wherein the phase shifter applies an activation such that a phase shifts in the third-wavelength light to achieve a phase walk-off that is an odd multiple of 180 degrees.

13. The optical waveguide structure of claim 2 , wherein the first-wavelength light travels in a first loop through a main segment between a first main location and a second main location within the main nonlinear optical waveguide, through the first extension optical waveguide, and through the first wavelength-selective coupler and the second wavelength-selective coupler, in which the first loop has a first length, and

wherein the second-wavelength light travels in a second loop through the main segment between the first main location and the second main location within the main nonlinear optical waveguide, through a secondary segment in the secondary optical waveguide, through the second extension optical waveguide, and through the first wavelength-selective coupler and the second wavelength-selective coupler, in which the second loop has a second length for the second-wavelength light.

14. The optical waveguide structure of claim 13 further comprising:

a phase shifter located adjacent to a portion of the main nonlinear optical waveguide, wherein the phase shifter applies an activation such that a phase shifts in the first-wavelength light to achieve a resonance condition for the first-wavelength light.

15. The optical waveguide structure of claim 13 further comprising:

a phase shifter located adjacent to a portion of the second extension optical waveguide, wherein the phase shifter applies an activation such that a phase shifts in the second-wavelength light to achieve a resonance condition for the second-wavelength light.

16. The optical waveguide structure of claim 2 , wherein the first-wavelength light is a pump light and the second-wavelength light is one of a signal light and an idler light, and wherein an intensity of the first-wavelength light is greater than an intensity of the second-wavelength light.

17. The optical waveguide structure of claim 2 , wherein the second extension optical waveguide is comprised of at least one of an electro-optical material, a nonlinear optical material or a non-nonlinear optical material.

18. The optical waveguide structure of claim 2 , wherein the second extension optical waveguide is comprised of an electro-optic material.

19. The optical waveguide structure of claim 2 , wherein the first wavelength-selective coupler, the second wavelength-selective coupler, the third wavelength-selective coupler, and the fourth wavelength-selective coupler are selected from at least one of a two-waveguide coupler, a multi-mode interference coupler, a pulley coupler, a Mach-Zehnder interferometer, or a 4-port micro-optical waveguide resonator coupler.

20. The optical waveguide structure of claim 2 further comprising:

a phase shifter located adjacent to a portion of the second extension optical waveguide, wherein the phase shifter applies an activation such that a phase shifts in the second-wavelength light to achieve a round-trip phase matching condition for a nonlinear optical process involving the second-wavelength light.

21. The optical waveguide structure of claim 2 further comprising:

a phase shifter located adjacent to a portion of the second extension optical waveguide, wherein the phase shifter applies an activation such that a phase shifts in the second-wavelength light to achieve a phase walk-off that is an odd multiple of 180 degrees.

22. The optical waveguide structure of claim 1 , wherein the main nonlinear optical waveguide is comprised of an electro-optic material.

23. The optical waveguide structure of claim 1 , wherein the main nonlinear optical waveguide is comprised of a nonlinear optical material.

24. The optical waveguide structure of claim 1 further comprising:

a phase shifter located adjacent to a portion of the main nonlinear optical waveguide, wherein the phase shifter applies an activation such that a phase shifts in the first-wavelength light to achieve a round-trip phase matching condition for a nonlinear optical process involving the first-wavelength light.

25. The optical waveguide structure of claim 1 further comprising:

a phase shifter located adjacent to a portion of the main nonlinear optical waveguide, wherein the phase shifter applies an activation such that a phase shifts in the first-wavelength light to achieve a phase walk-off that is an odd multiple of 180 degrees.

26. A method for facilitating a non-linear optical process comprising:

routing a first-wavelength light and a second-wavelength light in a main nonlinear optical waveguide;

optically coupling, by a first wavelength-selective coupler, the main nonlinear optical waveguide and an extension optical waveguide to each other such that the first-wavelength light is coupled from the main nonlinear optical waveguide to the extension optical waveguide and the second-wavelength light is not coupled from the main nonlinear optical waveguide to the extension optical waveguide but rather is coupled to a secondary optical waveguide; and

optically coupling, by a second wavelength-selective coupler, the main nonlinear optical waveguide and the extension optical waveguide to each other such that the first-wavelength light is coupled from the extension optical waveguide to the main nonlinear optical waveguide.

27. The method of claim 26 further comprising:

optically coupling, by a third wavelength-selective coupler, the secondary optical waveguide and a second extension optical waveguide to each other such that the second-wavelength light is coupled from the secondary optical waveguide to the second extension optical waveguide, and such that a third-wavelength light is not coupled from the secondary optical waveguide to the second extension optical waveguide; and

optically coupling, by a fourth wavelength-selective coupler, the secondary optical waveguide and the second extension optical waveguide to each other such that the second-wavelength light is coupled from the second extension optical waveguide to the secondary optical waveguide.

28. The method of claim 27 comprising:

routing the third-wavelength light in the main nonlinear optical waveguide;

optically coupling, by the third wavelength-selective coupler, the secondary optical waveguide and a third extension optical waveguide to each other such that the third-wavelength light is coupled from the secondary optical waveguide to the third extension optical waveguide and the second-wavelength light is not coupled from the secondary optical waveguide to the third extension optical waveguide; and optically coupling, by the fourth wavelength-selective coupler, the secondary optical waveguide and the third extension optical waveguide to each other such that the third-wavelength light is coupled from the third extension optical waveguide to the secondary optical waveguide.

29. The method of claim 28 , wherein the first-wavelength light travels in a first loop through a main segment between a first main location and a second main location within the main nonlinear optical waveguide and through a first extension optical waveguide, in which the first loop has a first length selected to achieve a resonance condition for the first-wavelength light;

wherein the second-wavelength light travels in a second loop through a segment in the secondary optical waveguide, through the second extension optical waveguide, and through the main segment in the main nonlinear optical waveguide, in which the second loop has a second length for the second-wavelength light selected to achieve the resonance condition for the second-wavelength light; and

wherein the third-wavelength light travels in a third loop through the segment in the secondary optical waveguide, through the third extension optical waveguide, and through the main segment in the main nonlinear optical waveguide, in which the third loop as a third length selected to achieve the resonance condition for the third-wavelength light.

30. The method of claim 29 further comprising:

applying an activation to a portion of the third extension optical waveguide such that such that a phase shifts in the third-wavelength light to achieve a resonance condition for the third-wavelength light.

31. The method of claim 27 , wherein the first-wavelength light travels in a first loop through a main segment between a first main location and a second main location within the main nonlinear optical waveguide and through a first extension segment, in which the first loop has a first length selected to achieve a resonance condition for the first-wavelength light; and

wherein the second-wavelength light travels in a second loop through a secondary segment in the secondary optical waveguide, through the second extension optical waveguide, and through the main segment in the main nonlinear optical waveguide, in which the second loop has a second length for the second-wavelength light selected to achieve the resonance condition for the second-wavelength light.

32. The method of claim 27 , wherein the first-wavelength light is a pump light, the second-wavelength light is one of a signal light and an idler light.

33. The method of claim 27 , wherein the first-wavelength light is one of a signal light and an idler light and the second-wavelength light is a pump light.

34. The method of claim 27 , wherein the first-wavelength light is a pump light, the second-wavelength light is a signal light, and the third-wavelength light is an idler light.

35. The method of claim 27 further comprising:

applying an activation such to a portion of the second extension optical waveguide such that a phase shifts in the second-wavelength light to achieve a resonance condition for the second-wavelength light.

36. The method of claim 27 further comprising:

applying an activation to a portion of the second extension optical waveguide such that a phase shifts in the second-wavelength light.

37. The method of claim 27 further comprising:

applying an activation to a portion of the main nonlinear optical waveguide such that a phase shifts in the first-wavelength light to achieve a round trip phase matching condition for a nonlinear optical process involving the first-wavelength light, the second-wavelength light and the third-wavelength light.

38. The method of claim 26 further comprising:

applying an activation to a portion of the main nonlinear optical waveguide such that a phase shifts in the first-wavelength light to achieve a resonance condition for the first-wavelength light.