Integrated opto-electronic oscillators

1. An opto-electronic device, comprising:

a substrate;

first and second waveguides formed on the substrate;

a first grating coupler formed in the first waveguide to couple input light incident to the substrate into the first waveguide;

an optical resonator in optical communication with the first and second waveguides to exchange light;

an optical modulator coupled to the first waveguide and operable to modulate light in the first waveguide in response to an electrical modulation signal;

a photodetector positioned on the substrate to receive and convert an optical output from the second waveguide into an electrical signal; and

an electrical link coupled between the photodetector and the optical modulator to produce the electrical modulation signal from said electrical signal.

2. A device as in claim 1 , wherein the optical resonator is a micro resonator in whispering gallery modes.

3. A device as in claim 2 , wherein the micro resonator is monolithically formed on the substrate.

4. A device as in claim 2 , wherein the micro resonator is engaged to the substrate.

5. A device as in claim 4 , further comprising two fibers that are engaged between the micro resonator and the substrate to support the micro resonator above the substrate and provide the optical communication between the micro resonator and the first and second waveguides, respectively.

6. A device as in claim 4 , further comprising two GRIN lenses that are engaged between the micro resonator and the substrate to support the micro resonator above the substrate and provide the optical communication between the micro resonator and the first and second waveguides, respectively.

7. A device as in claim 1 , further comprising a second grating coupler coupled to the second waveguide to produce an optical output out of the substrate.

8. A device as in claim 1 , further comprising an optical gain section in at least one of the first and the second waveguides to amplify light.

9. A device as in claim 1 , wherein each waveguide comprises a multi-layer reflective stack as cladding.

10. A device as in claim 1 , wherein each waveguide comprises a Bragg grating near the optical resonator to effectuate optical coupling with the optical resonator.

11. A device as in claim 1 , wherein the optical resonator exhibits an electro-optic effect and is tunable in response to an applied electrical signal.

12. A device as in claim 1 , further comprising a Si chip that is engaged to the substrate, wherein the electrical link comprises a CMOS circuit formed on the Si chip.

13. A device as in claim 1 , wherein the electrical link comprises a voltage controlled phase shifter.

14. A device as in claim 1 , wherein the substrate is silicon, the photodetector is a III-V semiconductor detector, and the electrical link comprises a CMOS circuit element.

15. A device as in claim 1 , wherein the first and second waveguides, the optical resonator, and the optical modulator are optically linked to form an optical ring.

16. A device as in claim 1 , wherein the electrical link is connected to a circuit off the substrate.

17. A device as in claim 1 , wherein the optical resonator is evanescently coupled to the first waveguide at a first end facet of the first waveguide and to the second waveguide at a second end facet of the second waveguide.

18. A device as in claim 1 , wherein the optical resonator is engaged to the substrate and the optical resonator is fiber pigtailed with two fibers which are coupled to the first and second waveguides.