Dielectric photonic receivers and concentrators for radio frequency and microwave applications

• US 8,498,539 B1
• Filed: 04/21/2010
• Issued: 07/30/2013
• Est. Priority Date: 04/21/2009
• Status: Active Grant

• Current Assignee: Oewaves Incorporated
• Original Assignee: Oewaves Incorporated
• Inventors: Ilchenko, Vladimir, Savchenkov, Anatoliy, Matsko, Andrey B., Seidel, David, Maleki, Lute
• Primary Examiner(s): Bello, Agustin
• Application Number:
  US12/764,943
• Time in Patent Office: 1,196 Days
• Field of Search: 398115-131
• US Class Current: 398/115
• CPC Class Codes: H04B 10/90 Non-optical transmission systems, e.g. transmission systems employing non-photonic corpuscular radiation
• CPC Class Codes: H04B 2210/006 Devices for generating or processing an RF signal by optical means

Abstract

Techniques, devices and systems for using dielectric materials, without metal or electrically conductive materials, to construct photonic RF and microwave receivers and concentrators.

Claims

1. A method for receiving a radio frequency (RF) signal, comprising:

using an all-dielectric RF antenna free of a metal to wirelessly receive an RF signal;

coupling the RF signal received by the all-dielectric RF antenna into an all-dielectric RF waveguide free of a metal to guide the received RF signal away from the all-dielectric RF antenna;

coupling the received RF signal in the all-dielectric RF waveguide into an all-dielectric RF resonator free of a metal that stores RF energy of the received RF signal that is coupled into the all-dielectric RF resonator;

exposing an electro-optic material, which is free of a metal and exhibits an electro-optic effect, to the RF energy stored by the all-dielectric RF resonator;

coupling continuous wave (CW) light into the electro-optic material to mix the CW light with the RF energy stored by the all-dielectric RF resonator to cause optical modulation of the CW light to produce modulated light that carries the RF signal; and

processing the modulated light to extract the RF signal.

2. The method as in claim 1, comprising:

directing the modulated light produced by mixing the CW light with the RF energy stored by the all-dielectric RF resonator in the electro-optic material along a dielectric waveguide to an RF protected chamber in which the modulated light is processed to extract the RF signal.

3. The method as in claim 2, comprising:

using a photodiode inside the RF protected chamber to convert the modulated light into an electrical signal in extracting the RF signal.

4. The method as in claim 1, comprising:

placing the electro-optic material inside the all-dielectric RF resonator to expose the electro-optic material to the RF energy stored by the all-dielectric RF resonator.

5. The method as in claim 1, comprising:

placing the electro-optic material outside the all-dielectric RF resonator to be adjacent to the all-dielectric RF resonator to expose the electro-optic material to the RF energy stored by the all-dielectric RF resonator.

6. The method as in claim 1, wherein:

the electro-optic material is in an optical resonator.

7. The method as in claim 6, wherein:

the optical resonator is a whispering gallery mode optical resonator.

8. The method as in claim 1, comprising:

making the all-dielectric RF antenna to have a tapered structure.

9. The method as in claim 8, comprising:

making the all-dielectric RF antenna to include a tapered waveguide that has a larger first end that receives the received RF signal and a smaller second end, and a tapered waveguide section connected between the larger first end and the smaller second end and structured to have a cross section that reduces from the larger first end to the smaller second end and focuses the received RF signal towards the smaller second end.

10. The method as in claim 9, comprising:

making the all-dielectric RF waveguide to include a first tapered tip that is electromagnetically coupled to the smaller second end of the tapered dielectric RF antenna to receive the input RF signal and a narrow dielectric RF waveguide section connected to the first tapered tip to guide the RF input signal away from the first tapered tip.

11. The method as in claim 1, comprising:

separating the all-dielectric RF resonator from the all-dielectric RF waveguide by a gap; and

adjusting the gap to control coupling of the received RF signal in the all-dielectric RF waveguide into the all-dielectric RF resonator.

12. The method as in claim 1, comprising:

making the all-dielectric RF antenna to have a horn structure with a tapered shape that reduces in dimension towards the all-dielectric RF resonator.

13. The method as in claim 1, comprising:

structuring the all-dielectric RF antenna to efficiently receive the RF signal from the air; and

independently structuring the all-dielectric RF resonator to concentrate the RF energy in a small volume for efficient coupling with the electro-optic material.

14. The method as in claim 13, comprising:

structuring the all-dielectric RF resonator to include;

a first tapered waveguide side that has a larger first end and a smaller second end, and a tapered waveguide section connected between the larger first end and the smaller second end and structured to have a cross section that reduces from the larger first end to the smaller second end; and

a second tapered waveguide side that has a larger second end and a second tapered waveguide section connected to the larger second end and structured to (1) have a cross section that reduces from the larger second end and (2) connect to the smaller second end to form a waist section,

wherein the electro-optic material is located to interact with the RF signal at the waist section of the all-dielectric RF resonator.

15. The method as in claim 13, comprising:

structuring the all-dielectric RF resonator to include;

a dielectric cylindrical disk shaped to include a hollow cylindrical void inside dielectric cylindrical disk and off center from a symmetric axis of the dielectric cylindrical disk to form a narrow dielectric material section near an external side surface of the dielectric cylindrical disk; and

,

wherein the electro-optic material is located to interact with the RF signal at the narrow dielectric material section near the external side surface of the dielectric cylindrical disk.

16. A device for receiving a radio frequency (RF) signal, comprising:

an all-dielectric RF waveguide free of a metal including a first waveguide end that receives an RF signal and a second waveguide end to which the received RF signal is guided;

an all-dielectric RF resonator free of a metal that is electromagnetically coupled to the second waveguide end of the all-dielectric RF waveguide to receive and store RF energy of the RF signal;

an optical resonator, which is formed of a dielectric material exhibiting an electro-optic effect and free of a metal, positioned relative to the all-dielectric RF resonator to be exposed to RF energy stored by the all-dielectric RF resonator;

an optical coupling device coupling continuous wave (CW) light into the optical resonator to mix the CW light with the RF energy to cause optical modulation of the CW light based on the electro-optic effect to produce modulated light that carries the RF signal;

an all-dielectric optical waveguide coupled to receive the modulated light from the optical resonator and to guide the modulated light away from the optical resonator; and

an RF protected photodiode that receives the modulated light from the all-dielectric optical waveguide and converts the modulated light into an electrical signal representing the RF signal.

17. The device as in claim 16, wherein:

the optical resonator is a whispering gallery mode optical resonator.

18. The device as in claim 16, wherein:

the optical resonator is located inside the all-dielectric RF resonator.

19. The device as in claim 16, wherein:

the optical resonator is located outside the all-dielectric RF resonator to be adjacent to the all-dielectric RF resonator to be exposed to the RF energy stored by the all-dielectric RF resonator.

20. The device as in claim 16, comprising:

an all-dielectric RF antenna structured to wirelessly receive the RF signal from the air and electromagnetically coupled to the first waveguide end of the all-dielectric RF waveguide to couple the RF signal into the all-dielectric RF waveguide.

21. The device as in claim 20, wherein:

the all-dielectric RF antenna includes a tapered waveguide that has a larger first end that receives the RF signal and a smaller second end coupled to the first waveguide end of the all-dielectric RF waveguide, and a tapered waveguide section connected between the larger first end and the smaller second end and structured to have a cross section that reduces from the larger first end to the smaller second end and focuses the RF signal towards the smaller second end.

22. The device as in claim 16, wherein:

the first waveguide end of the all-dielectric RF waveguide is a first tapered tip and a narrow dielectric RF waveguide section connected to the first tapered tip to guide the RF input signal away from the first tapered tip.

23. The device as in claim 16, wherein:

the all-dielectric RF resonator is separate from the all-dielectric RF waveguide by a gap; and

a mechanism that adjusts the gap to control coupling of the RF signal in the all-dielectric RF waveguide into the all-dielectric RF resonator.

24. The device as in claim 16, wherein:

the all-dielectric RF resonator includes;

a first tapered waveguide side that has a larger first end and a smaller second end, and a tapered waveguide section connected between the larger first end and the smaller second end and structured to have a cross section that reduces from the larger first end to the smaller second end; and

a second tapered waveguide side that has a larger second end and a second tapered waveguide section connected to the larger second end and structured to (1) have a cross section that reduces from the larger second end and (2) connect to the smaller second end to form a waist section,

wherein the optical resonator is located to interact with the RF signal at the waist section of the all-dielectric RF resonator.

25. The device as in claim 16, wherein:

the all-dielectric RF resonator includes;

a dielectric cylindrical disk shaped to include a hollow cylindrical void inside dielectric cylindrical disk and off center from a symmetric axis of the dielectric cylindrical disk to form a narrow dielectric material section near an external side surface of the dielectric cylindrical disk; and

,

wherein the optical resonator is located to interact with the RF signal at the narrow dielectric material section near the external side surface of the dielectric cylindrical disk.

26. A device for receiving radio frequency (RF) signals, comprising:

a dielectric RF antenna structured to receive an input RF signal and to output the received input RF signal; and

an optical whispering gallery mode (WGM) resonator formed of an electro-optic material and located outside the dielectric RF antenna to directly receive the RF input signal to cause an electro-optic modulation of light in one or more WGM modes inside the optical WGM resonator based on interaction between the received input RF signal and the light in the electro-optic material so that the modulated light carries the input RF signal,

wherein;

the dielectric RF antenna is structured to have an input end with a large cross section that receives the input RF signal and an output end with a small cross section smaller that the large cross section, and a tapered waveguide horn section connected between the input end and the output end and structured to have a cross section that reduces from the input end to the output end to guide the input RF signal to the output end, the output end being structured to have a concave opening to form a cavity or notch for outputting the input RF signal.

27. The device as in claim 26, wherein:

the optical WGM resonator is structured to be axially or cylindrically symmetric around an optic axis of the electro-optic material around which the WG modes circulate in a circular path or the equator, and

the optical WGM resonator is oriented to have the optic axis in alignment of an axis of the a tapered waveguide horn section of the tapered dielectric antenna.

28. The device as in claim 26, comprising:

a phase grating formed on the input end to cause the input RF signal to have a nonzero momentum at the optical WGM resonator.

29. The device as in claim 26, comprising:

the dielectric RF antenna and the optical WGM resonator are free of a metallic component.

30. A device for receiving radio frequency (RF) signals, comprising:

a dielectric RF antenna structured to receive an input RF signal;

a dielectric RF waveguide that is electromagnetically coupled to the dielectric RF antenna to receive the input RF signal;

a dielectric RF resonator that is electromagnetically coupled to the dielectric RF waveguide section to receive the input RF signal and is structured to be in resonance with the received the RF input signal; and

an optical whispering gallery mode (WGM) resonator formed of an electro-optic material and located outside the dielectric RF resonator to be in electromagnetic coupling to the dielectric RF resonator to receive the RF input signal that interacts with the electro-optic material to cause an electro-optic modulation of light in one or more WGM modes inside the optical WGM resonator so that the modulated light carries the input RF signal,

wherein the dielectric RF antenna includes a cylindrical dielectric RF antenna section, and

wherein;

the dielectric RF resonator is spaced from the narrow dielectric RF waveguide section, and

the device comprises a mechanism that adjusts a spacing between the dielectric RF resonator and the narrow dielectric RF waveguide section.

31. The device as in claim 30, wherein:

the dielectric RF waveguide includes a first tapered tip that is electromagnetically coupled to the dielectric RF antenna to receive the input RF signal and a narrow dielectric RF waveguide section connected to the first tapered tip to guide the RF input signal away from the first tapered tip.

32. The device as in claim 30, wherein:

the dielectric RF antenna, the dielectric RF waveguide, the dielectric RF resonator and the optical WGM resonator are free of a metallic component.

33. The device as in claim 30, wherein:

the dielectric RF resonator includes;

a first tapered waveguide side that has a larger first end and a smaller second end, and a tapered waveguide section connected between the larger first end and the smaller second end and structured to have a cross section that reduces from the larger first end to the smaller second end; and

a second tapered waveguide side that has a larger second end and a second tapered waveguide section connected to the larger second end and structured to (1) have a cross section that reduces from the larger second end and (2) connect to the smaller second end to form a waist section,

wherein the optical WGM resonator is located to interact with the RF signal at the waist section of the all-dielectric RF resonator.

34. The device as in claim 30, wherein:

the dielectric RF resonator includes;

a dielectric cylindrical disk shaped to include a hollow cylindrical void inside dielectric cylindrical disk and off center from a symmetric axis of the dielectric cylindrical disk to form a narrow dielectric material section near an external side surface of the dielectric cylindrical disk; and

,

wherein the optical WGM resonator is located to interact with the RF signal at the narrow dielectric material section near the external side surface of the dielectric cylindrical disk.

35. A device for receiving radio frequency (RF) signals, comprising:

a tapered dielectric RF antenna structured to receive an input RF signal and to include a tapered waveguide that has a larger first end that receives the received input RF signal and a smaller second end, and a tapered waveguide section connected between the larger first end and the smaller second end and structured to have a cross section that reduces from the larger first end to the smaller second end and focuses the received input RF signal towards the smaller second end;

a narrow dielectric RF waveguide including a first tapered tip that is electromagnetically coupled to the smaller second end of the tapered dielectric RF antenna to receive the input RF signal and a narrow dielectric RF waveguide section connected to the first tapered tip to guide the RF input signal away from the first tapered tip;

a dielectric RF resonator that is electromagnetically coupled to the narrow dielectric RF waveguide section to receive the input RF signal and is structured to be in resonance with the received the RF input signal; and

an optical whispering gallery mode (WGM) resonator formed of an electro-optic material and located outside the dielectric RF resonator to be in electromagnetic coupling to the dielectric RF resonator to receive the RF input signal that interacts with the electro-optic material to cause an electro-optic modulation of light in one or more WGM modes inside the optical WGM resonator so that the modulated light carries the input RF signal.

36. The device as in claim 35, wherein:

the optical WGM resonator is structured to be axially or cylindrically symmetric around an optic axis of the electro-optic material around which the WG modes circulate in a circular path or the equator, and

the optical WGM resonator is oriented to have the optic axis parallel to an electric polarization of the input RF signal.

37. The device as in claim 35, wherein:

the optical WGM resonator is structured to be axially or cylindrically symmetric around an optic axis of the electro-optic material around which the WG modes circulate in a circular path or the equator, and

the optical WGM resonator is oriented to have the optic axis perpendicular to an electric polarization of the input RF signal.

38. The device as in claim 35, comprising:

an optical coupler coupled to the optical WGM resonator to coupling light into the optical WGM resonator and to coupling the modulated light of the optical WGM resonator.

39. The device as in claim 35, wherein:

the dielectric RF resonator is spaced from the narrow dielectric RF waveguide section,

the device comprises a mechanism that adjusts a spacing between the dielectric RF resonator and the narrow dielectric RF waveguide section.

40. The device as in claim 35, wherein:

the tapered dielectric RF antenna, the narrow dielectric RF waveguide, the dielectric RF resonator and the optical WGM resonator are free of a metallic component.

41. The device as in claim 35, wherein:

the dielectric RF resonator includes;

a first tapered waveguide side that has a larger first end and a smaller second end, and a tapered waveguide section connected between the larger first end and the smaller second end and structured to have a cross section that reduces from the larger first end to the smaller second end; and

a second tapered waveguide side that has a larger second end and a second tapered waveguide section connected to the larger second end and structured to (1) have a cross section that reduces from the larger second end and (2) connect to the smaller second end to form a waist section,

wherein the optical WGM resonator is located to interact with the RF signal at the waist section of the dielectric RF resonator.

42. The device as in claim 35, wherein:

the dielectric RF resonator includes;

a dielectric cylindrical disk shaped to include a hollow cylindrical void inside dielectric cylindrical disk and off center from a symmetric axis of the dielectric cylindrical disk to form a narrow dielectric material section near an external side surface of the dielectric cylindrical disk; and

,

wherein the optical WGM resonator is located to interact with the RF signal at the narrow dielectric material section near the external side surface of the dielectric cylindrical disk.

43. A device for receiving radio frequency (RF) signals, comprising

a dielectric RF resonator antenna that receives and stores an RF signal without carrying an optical beam, and includes:

a first tapered waveguide side that has a larger first end and a smaller second end, and a tapered waveguide section connected between the larger first end and the smaller second end and structured to have a cross section that reduces from the larger first end to the smaller second end, and

a second tapered waveguide side that has a larger second end and a second tapered waveguide section connected to the larger second end and structured to (1) have a cross section that reduces from the larger second end and (2) connect to the smaller second end to form a waist section, wherein the first tapered waveguide section and the second tapered waveguide section receive the RF signal and concentrate the received RF signal to the waist section with a higher RF intensity; and

an optical resonator that exhibits an electro-optic effect and is located to interact with the RF signal at the waist section of the dielectric RF resonator antenna to modulate optical light inside the optical resonator to produce modulated light that carries the RF signal initially received by the RF resonator antenna.

44. The device as in claim 43, wherein:

the dielectric RF resonator is made of a dielectric material with a refractive index for the RF signal is 10 and

the first and second tapered waveguide sides are structured to concentrate the RF signal at the waist section with a volume of 10<sup>−

6</sup> cm³.

48. The device as in claim 43, wherein:

the RF resonator antenna includes a straight dielectric waveguide section with a small cross section in the waist section between the first and second tapered waveguide sections.

45. A device for receiving radio frequency (RF) signals, comprising:

a dielectric RF horn antenna that receives an RF signal;

a dielectric waveguide taper coupled to the dielectric RF horn antenna to direct the received RF signal from the RF horn antenna to a narrow part of the dielectric waveguide taper to increase an intensity of the received RF signal;

a dielectric RF resonator which is coupled to the dielectric waveguide taper to receive the RF signal and store the received RF signal and includes;

a dielectric cylindrical disk shaped to include a hollow cylindrical void inside dielectric cylindrical disk and off center from a symmetric axis of the dielectric cylindrical disk to form a narrow dielectric material section near an external side surface of the dielectric cylindrical disk; and

,

an optical resonator located to interact with the RF signal at the narrow dielectric material section near the external side surface of the dielectric cylindrical disk.

46. The device as in claim 45, wherein:

the optical resonator exhibits an electro-optic effect and, in response to the RF signal at the narrow dielectric material section, modulates optical light inside the optical resonator to produce modulated light that carries the RF signal initially received by the RF horn antenna.

47. The device as in claim 45, comprising:

a mechanism that adjusts a spacing between the dielectric RF resonator and the dielectric waveguide taper to provide an adjustable coupling gap.