Integrated optical disk resonator

• US 7,933,022 B2
• Filed: 12/29/2006
• Issued: 04/26/2011
• Est. Priority Date: 12/01/2006
• Status: Expired due to Fees

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Smith, Terry L., Koch, Barry J., Yi, Yasha
• Primary Examiner(s): LEE, HWA S
• Application Number:
  US11/617,923
• Publication Number:
  US 20090310140A1
• Time in Patent Office: 1,579 Days
• Field of Search: 356/454, 356/480
• US Class Current: 356/480
• CPC Class Codes: G01N 2021/7776 Index
• CPC Class Codes: G01N 21/7746 the waveguide coupled to a cavity resonator
• CPC Class Codes: G02B 6/12007 forming wavelength selective elements, e.g. multiplexer, demultiplexer

Abstract

A method and system are disclosed for detecting the presence of a perturbation of a microresonator including the step of exciting at least first and second resonant guided optical modes of a microresonator with a light source that is in optical communication with the microresonator. The method further includes inducing a first frequency shift in the first resonant guided optical mode and a second frequency shift in the second resonant guided optical mode, wherein the second frequency shift can be zero. Another step of the method is comparing the first frequency shift and the second frequency shift.

Claims

1. A method of detecting the presence of a perturbation of a microresonator comprising:

exciting at least first and second resonant guided optical modes of a microresonator with a light source that is in optical communication with the microresonator;

inducing a first frequency shift in the first resonant guided optical mode and a second frequency shift in the second resonant guided optical mode, wherein the second frequency shift can be zero; and

comparing the first frequency shift and the second frequency shift.

2. The method of claim 1 wherein the second frequency shift is zero, so that the difference between the first frequency shift and the second frequency shift is equal to the first frequency shift.

3. The method of claim 1 wherein the second frequency shift is non-zero.

4. The method of claim 1 further comprising the step of determining that a perturbation is present if the first frequency shift is different than the second frequency shift.

5. The method of claim 1 wherein the step of comparing comprises determining a difference between the first frequency shift and the second frequency shift.

6. The method of claim 1 further comprising the step of providing an optical sensing system comprising:

the light source;

one or more bus waveguides, the one or more bus waveguides comprising a first bus waveguide that has an input port that is in optical communication with the light source; and

the microresonator optically coupled to the one or more bus waveguides.

7. The method of claim 6, further comprising the step of:

detecting the first and second guided optical modes at a detector located at the through port.

8. The method of claim 6, wherein the optical sensing system further comprises a second bus waveguide having a drop port, wherein the second bus waveguide is in optical communication with the light source and with the microresonator, further comprising the step of:

detecting the first and second guided optical modes at a detector located at the drop port.

9. The method of claim 6 wherein the microresonator and the first bus waveguide are integrated on a substrate.

10. The method of claim 1 wherein the step of inducing the first frequency shift in the first resonant guided optical mode comprises causing a perturbation of the microresonator.

11. The method of claim 10 wherein the step of inducing the first frequency shift in the first resonant guided optical mode comprises changing a refractive index of at least a portion of a surface of the microresonator.

12. The method of claim 10 wherein the step of inducing the first frequency shift in the first resonant guided optical mode comprises changing a strength of optical coupling between a scattering center and the microresonator.

13. The method of claim 12 wherein the scattering center is a nanoparticle.

14. The method of claim 13 wherein the scattering center is a metallic, semiconductor, dielectric or metamaterial nanoparticle.

15. The method of claim 12 wherein the step of changing the strength of optical coupling between a scattering center and the microresonator further comprises changing an index of refraction of the scattering center.

16. The method of claim 12 wherein the step of changing the strength of optical coupling between a scattering center and the microresonator further comprises changing a distance between the scattering center and the microresonator.

17. The method of claim 1 wherein the step of exciting at least first and second resonant optical modes comprises the steps of:

exciting third and fourth resonant optical modes of the microresonator with the light source;

scattering the third and fourth optical modes into the first and second optical modes by an interaction of the third and fourth optical modes with a first optical scattering center.

18. The method of claim 17 wherein the first scattering center of the microresonator comprises a scattering portion of a core of the microresonator having an index of refraction that is different than an index of refraction of a remainder of a core of a microresonator.

19. The method of claim 17 wherein the first scattering center of the microresonator comprises a surface having a mean square roughness of at least 50 nanometers on at least a portion of a surface of the microresonator.

20. The method of claim 17 wherein the microresonator is a polygonal microresonator and the first scattering center of the microresonator comprises at least one of a plurality of angled surfaces of a core of the microresonator.

21. The method of claim 17, wherein a first bus waveguide is in optical communication with a light source and with the microresonator, the first bus waveguide having an input port and a through port, wherein the light source is located at the input port, further comprising the step of:

detecting the third and fourth guided optical modes at a detector located at the through port.

22. The method of claim 17, wherein a first bus waveguide is in optical communication with a light source and with the microresonator, the first bus waveguide having an input port where the light source is located, further comprising the step of:

detecting the first and second optical modes at a detector located at the input port.

23. The method of claim 17, wherein a first bus waveguide having an input port and second bus waveguide having a drop port are in optical communication with a light source and with the microresonator, wherein the light source is located at the input port, further comprising the step of:

detecting the third and fourth guided optical modes at a detector located at the drop port.

24. The method of claim 17, wherein a first bus waveguide having an input port and second bus waveguide having a drop port and a drop 2 port are in optical communication with a light source and with the microresonator, further comprising the step of:

detecting the first and second guided optical modes at a detector located at the drop 2 port.

25. A method of detecting the presence of a perturbation of a microresonator comprising:

exciting at least first and second resonant guided optical modes of a microresonator with a light source that is in optical communication with the microresonator, wherein the microresonator includes a first optical scattering center, wherein the first and second resonant guided optical modes are scattered into at least third and fourth guided optical modes by the first scattering center;

inducing a first frequency shift in the first optical mode and a second frequency shift in the second guided optical mode, wherein the second frequency shift can be zero, wherein the first and second frequency-shifted resonant guided optical modes are scattered into at least fifth and sixth guided optical modes by the first scattering center;

detecting the third, fourth, fifth and sixth guided optical modes at a detector located at a center location of the microresonator;

comparing a first frequency difference between third and fifth guided optical modes with a second frequency difference between the fourth and sixth guided optical modes.

26. The method of claim 25 wherein the first scattering center of the microresonator comprises a scattering portion of a core of the microresonator having an index of refraction that is different than an index of refraction of a remainder of a core of a microresonator.

27. The method of claim 25 wherein the first scattering center of the microresonator comprises a surface having a mean square roughness of at least 50 nanometers on at least a portion of a surface of the microresonator.

28. The method of claim 25 wherein the microresonator is a polygonal microresonator and the first scattering center of the microresonator comprises at least one of a plurality of angled surfaces of a core of the microresonator.

29. The method of claim 25 wherein the step of inducing the first frequency shift in the first resonant guided optical mode comprises causing a perturbation of the microresonator.

30. The method of claim 29 wherein the step of inducing the first frequency shift in the first resonant guided optical mode comprises changing a refractive index of at least a portion of a surface of the microresonator.

31. The method of claim 29 wherein the step of inducing the first frequency shift in the first resonant guided optical mode comprises changing a strength of optical coupling between a second optical scattering center and the microresonator.

32. The method of claim 31 wherein the second scattering center is a nanoparticle.

33. The method of claim 32 wherein the second scattering center is a metallic, semiconductor, dielectric or metamaterial nanoparticle.

34. The method of claim 31 wherein the step of changing the strength of optical coupling between a second optical scattering center and the microresonator further comprises changing a distance between the second scattering center and the microresonator.

35. The method of claim 25, wherein a first bus waveguide having an input port and second bus waveguide having a drop port and a drop 2 port are in optical communication with a light source and with the microresonator, further comprising the step of:

detecting the third and fourth optical modes at a detector located at the drop 2 port; and

detecting third and fourth frequency-shifted optical modes at the detector located at the drop 2 port.

36. The method of claim 31 wherein the step of changing the strength of optical coupling between a second optical scattering center and the microresonator further comprises changing an index of refraction of the second scattering center.