Generation of single optical tone, RF oscillation signal and optical comb in a triple-oscillator device based on nonlinear optical resonator

1. A triple-oscillator device for generating a single optical tone, a radio frequency (RF) oscillation signal and an optical frequency comb signal having different optical frequencies, comprising:

an optical resonator formed of a nonlinear optical material exhibiting a third order optical nonlinearity;

laser to produce a continuous wave (CW) laser beam at a laser carrier frequency that interacts with the nonlinear optical material of the optical resonator to generate the optical frequency comb having different optical frequencies including the laser carrier frequency inside the optical resonator;

an optical coupler that couples the laser beam into the optical resonator and light inside the optical resonator out of the optical resonator as a self-injection feedback beam towards the laser;

an optical filter located between the laser and the optical resonator to filter the self-injection feedback beam directed from the optical coupler to the laser to direct light at the laser carrier frequency into the laser to cause injection locking of the laser to the optical resonator at the laser carrier frequency while blocking other spectral components in the self-injection feedback beam from entering the laser;

a first beam splitter placed between the laser and the optical filter to transmit a portion of the light between the laser and the optical filter and to direct another portion of the light as a first device output which is a single optical tone at the laser carrier frequency;

a photodiode located to receive an output optical beam coupled out of the optical resonator carrying the optical frequency comb to produce an RF oscillation signal as a second device output; and

a second beam splitter located in an optical path of the output optical beam received by the photodiode to transmit a portion of the output optical beam to the photodiode for generating the RF oscillation signal and to direct another portion of the output optical beam as a third device output which is a replica of the optical frequency comb generated inside the optical resonator.

2. The device as in claim 1 , wherein the laser is a semiconductor laser.

3. The device as in claim 1 , comprising:

a substrate on which the optical resonator is located; and

an optical waveguide formed on the substrate that carries the laser beam from the laser to the optical resonator and to carry the output optical beam from the optical resonator having the optical comb.

4. The device as in claim 1 , comprising:

a phase control section located between the laser and the optical resonator and configured to control a phase of the light between the laser and the optical resonator to stabilize the device and control a frequency detuning between the laser carrier frequency and a resonator mode of the optical resonator with respect to which the laser is injection locked.

5. The device as in claim 4 , wherein the phase control section includes a thermal heater that changes a temperature of the phase control section to control the phase of the light between the laser and the optical resonator.

6. The device as in claim 4 , wherein the phase control section includes a piezo-electric element that changes the phase of the light between the laser and the optical resonator.

7. The device as in claim 4 , wherein the phase control section includes a semiconductor phase shifter that changes the phase of the light between the laser and the optical resonator.

8. The device as in claim 4 , wherein the phase control section is configured to produce an adjustable delay that changes the phase of the light between the laser and the optical resonator.

9. The device as in claim 1 , wherein the optical coupler is used to couple both the laser beam from the laser into the optical resonator and to couple light inside the optical resonator out as the output optical beam to the photodiode.

10. The device as in claim 1 , comprising:

a second optical coupler optically coupled to the optical resonator to couple light inside the optical resonator out as the output optical beam to the photodiode.

11. The device as in claim 1 , wherein:

the optical resonator is a whispering-gallery-mode resonator that supports whispering gallery modes, and

the optical coupler is an optical evanescent coupler.

12. A triple-oscillator device for generating a single optical tone, a radio frequency (RF) oscillation signal and an optical frequency comb signal having different optical frequencies, comprising:

an optical resonator formed of a nonlinear optical material exhibiting a third order optical nonlinearity;

a reflective amplifier that reflects light and amplifies light from the optical resonator to direct reflected light towards the optical resonator to interact with the nonlinear optical material of the optical resonator to generate the optical frequency comb having different optical frequencies inside the optical resonator, the reflective amplifier providing an optical gain to sustain laser oscillation between the reflective amplifier and the optical resonator at a laser carrier frequency;

an optical coupler that couples the light from the reflective amplifier into the optical resonator and light inside the optical resonator out of the optical resonator as a feedback beam towards the reflective amplifier and further couples light from the reflective amplifier into the optical resonator;

an optical filter located between the reflective amplifier and the optical resonator to filter the feedback beam directed from the optical coupler to the reflective amplifier to direct light at the laser carrier frequency within the feedback beam into the reflective amplifier to cause amplification of the light at the laser carrier frequency;

a first beam splitter placed between the reflective amplifier and the optical filter to transmit a portion of the light between the reflective amplifier and the optical filter and to direct another portion of the light as a first device output which is a single optical tone at the laser carrier frequency;

a photodiode located to receive an output optical beam coupled out of the optical resonator carrying the optical frequency comb to produce an RF oscillation signal as a second device output; and

a second beam splitter located in an optical path of the output optical beam received by the photodiode to transmit a portion of the output optical beam to the photodiode for generating the RF oscillation signal and to direct another portion of the output optical beam as a third device output which is a replica of the optical frequency comb generated inside the optical resonator.

13. The device as in claim 12 , comprising:

a substrate on which the optical resonator is located; and

an optical waveguide formed on the substrate that carries the light from the reflective amplifier to the optical resonator and to carry the output optical beam from the optical resonator having the optical frequency comb.

14. The device as in claim 12 , comprising:

a phase control section located between the reflective amplifier and the optical resonator and configured to control a phase of the light between the reflective amplifier and the optical resonator.

15. The device as in claim 14 , wherein the phase control section includes a thermal heater that changes a temperature of the phase control section to control the phase of the light between the reflective amplifier and the optical resonator.

16. The device as in claim 14 , wherein the phase control section includes a piezo-electric element that changes the phase of the light between the reflective amplifier and the optical resonator.

17. The device as in claim 14 , wherein the phase control section includes a semiconductor phase shifter that changes the phase of the light between the reflective amplifier and the optical resonator.

18. The device as in claim 14 , wherein the phase control section is configured to produce an adjustable delay that changes the phase of the light between the reflective amplifier and the optical resonator.

19. The device as in claim 12 , wherein the optical coupler is used to couple both the light from the reflective amplifier into the optical resonator and to couple light inside the optical resonator out as the output optical beam to the photodiode.

20. The device as in claim 12 , comprising:

a second optical coupler optically coupled to the optical resonator to couple light inside the optical resonator out as the output optical beam to the photodiode.

21. The device as in claim 12 , wherein:

the optical resonator is a whispering-gallery-mode resonator that supports whispering gallery modes, and

the optical coupler is an optical evanescent coupler.

22. A triple-oscillator device for generating a single optical tone, a radio frequency (RF) oscillation signal and an optical frequency comb signal having different optical frequencies, comprising:

an optical resonator formed of a nonlinear optical material exhibiting a third order optical nonlinearity;

a laser to produce a continuous wave (CW) laser beam at a laser carrier frequency that interacts with the nonlinear optical material of the optical resonator to generate the optical frequency comb having different optical frequencies including the laser carrier frequency inside the optical resonator;

an optical coupler that couples the laser beam into the optical resonator and light inside the optical resonator out of the optical resonator as a self-injection feedback beam towards the laser;

an optical filter located between the laser and the optical resonator to filter the self-injection feedback beam directed from the optical coupler to the laser to direct light at the laser carrier frequency into the laser to cause injection locking of the laser to the optical resonator at the laser carrier frequency while blocking other spectral components in the self-injection feedback beam from entering the laser;

means for transmitting a portion of the light between the laser and the optical filter and for directing another portion of the light as a first device output which is a single optical tone at the laser carrier frequency;

a photodiode located to receive an output optical beam coupled out of the optical resonator carrying the optical frequency comb to produce an RF oscillation signal as a second device output; and

means for splitting the output optical beam towards the photodiode into (1) a first portion of the output optical beam to reach the photodiode which generates the RF oscillation signal from the first portion and (2) a second portion of the output optical beam as a third device output which is a replica of the optical frequency comb generated inside the optical resonator.

23. The device as in claim 22 , wherein the laser is a semiconductor laser.

24. The device as in claim 22 , comprising:

a substrate on which the resonator is located; and

an optical waveguide formed on the substrate that carries the laser beam from the laser to the optical resonator and to carry the output optical beam from the optical resonator having the optical comb.

25. The device as in claim 22 , comprising:

a phase control section located between the laser and the optical resonator and configured to control a phase of the light between the laser and the optical resonator to stabilize the device and control a frequency detuning between the laser carrier frequency and a resonator mode of the optical resonator with respect to which the laser is injection locked.

26. A triple-oscillator device for generating a single optical tone, a radio frequency (RF) oscillation signal and an optical frequency comb signal having different optical frequencies, comprising:

an optical resonator formed of a nonlinear optical material exhibiting a third order optical nonlinearity;

a reflective amplifier that reflects light and amplifies light from the optical resonator to direct reflected light towards the optical resonator to interact with the nonlinear optical material of the optical resonator to generate the optical frequency comb having different optical frequencies inside the optical resonator, the reflective amplifier providing an optical gain to sustain laser oscillation between the reflective amplifier and the optical resonator at a laser carrier frequency;

means for coupling the light from the reflective amplifier into the optical resonator and light inside the optical resonator out of the optical resonator as a feedback beam towards the reflective amplifier and for coupling light from the reflective amplifier into the optical resonator;

an optical filter located between the reflective amplifier and the optical resonator to filter the feedback beam to the reflective amplifier and to direct light at the laser carrier frequency within the feedback beam into the reflective amplifier to cause amplification of the light at the laser carrier frequency;

means for transmitting a portion of the light between the reflective amplifier and the optical filter and for directing another portion of the light as a first device output which is a single optical tone at the laser carrier frequency;

a photodiode located to receive an output optical beam coupled out of the optical resonator carrying the optical frequency comb to produce an RF oscillation signal as a second device output; and

means for transmitting a first portion of the output optical beam towards the photodiode which generates the RF oscillation signal from the first portion and for directing a second portion of the output optical beam as a third device output which is a replica of the optical frequency comb generated inside the optical resonator.

27. The device as in claim 26 , comprising:

a substrate on which the optical resonator is located; and

an optical waveguide formed on the substrate that carries the light from the reflective amplifier to the optical resonator and to carry the output optical beam from the optical resonator having the optical frequency comb.

28. The device as in claim 26 , comprising:

a phase control section located between the reflective amplifier and the optical resonator and configured to control a phase of the light between the reflective amplifier and the optical resonator.