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

• US 20120294319A1
• Filed: 05/15/2012
• Published: 11/22/2012
• Est. Priority Date: 05/16/2011
• Status: Active Grant

• Current Assignee: Oewaves Incorporated
• Original Assignee: Oewaves Incorporated
• Inventors: Maleki, Lute, Matsko, Andrey
• Granted Patent: US 8,681,827 B2
• Time in Patent Office: Days
• US Class Current: 372/18
• CPC Class Codes: G02F 1/3536 Four-wave interaction
• CPC Class Codes: G02F 1/39 for parametric generation or amplification of light, infrared or ultraviolet waves
• CPC Class Codes: G02F 2/00 Demodulating light; Transferring the modulation of modulated light; Frequency-changing of light G02F1/35 takes precedence
• CPC Class Codes: G02F 2203/15 involving resonance effects, e.g. resonantly enhanced interaction
• CPC Class Codes: G02F 2203/56 Frequency comb synthesizer
• CPC Class Codes: H01S 3/0092 Nonlinear frequency conversion, e.g. second harmonic generation [SHG] or sum- or difference-frequency generation outside the laser cavity nonlinear frequency conversion per se G02F1/35
• CPC Class Codes: H03B 17/00 Generation of oscillations using radiation source and detector, e.g. with interposed variable obturator
• CPC Class Codes: H04B 2210/006 Devices for generating or processing an RF signal by optical means

Abstract

Techniques and devices based on optical resonators made of nonlinear optical materials to form triple-oscillator devices for generating a single optical tone, a radio frequency (RF) oscillation signal and an optical frequency comb signal having different optical frequencies.

Claims

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;

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

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

an optical filter located between the laser and the resonator to filter the self-injection feedback beam directed from the optical evanescent coupler to the laser to direct light at the laser carrier frequency into the laser to cause injection locking of the laser to the 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 beam between the laser and the optical filter and to direct another portion of the beam 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 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 output optical beam to the photodiode for generating the RF oscillation signal and to direct another portion of the beam as a third device output which is a replica of the optical frequency comb generated inside the 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 resonator is located; and

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

4. The device as in claim 1, comprising:

a phase control section located between the laser and the resonator and configured to control a phase of the light between the laser and the resonator to stabilize the device and control a frequency detuning between the laser carrier frequency and a resonator mode of the 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 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 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 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 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 resonator and to couple light inside the 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 resonator to couple light inside the resonator out as the output optical beam to the photodiode.

11. The device as in claim 1, wherein:

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

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

an optical filter located between the reflective amplifier and the 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 beam between the reflective amplifier and the optical filter and to direct another portion of the beam 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 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 output optical beam to the photodiode for generating the RF oscillation signal and to direct another portion of the beam as a third device output which is a replica of the optical frequency comb generated inside the resonator.

13. The device as in claim 12, comprising:

a substrate on which the resonator is located; and

an optical waveguide formed on the substrate that carries the light from the reflective amplifier to the resonator and to carry the output optical beam from the 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 resonator and configured to control a phase of the light between the reflective amplifier and the 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 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 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 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 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 resonator and to couple light inside the 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 resonator to couple light inside the resonator out as the output optical beam to the photodiode.

21. The device as in claim 12, wherein:

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

the optical coupler is an optical evanescent coupler.