METHOD AND APPARATUS FOR OPTICAL FREQUENCY COMB GENERATION USING A MONOLITHIC MICRO-RESONATOR

• US 20080285606A1
• Filed: 05/05/2008
• Published: 11/20/2008
• Est. Priority Date: 05/04/2007
• Status: Active Grant

• Current Assignee: Max-Planck-Gesellschaft Zur Foerderung Der Wissenschaften e.V. (Max-Planck-Gesellschaft zur Frderung der Wissenschaften e)
• Original Assignee: Max-Planck-Gesellschaft Zur Foerderung Der Wissenschaften e.V. (Max-Planck-Gesellschaft zur Frderung der Wissenschaften e)
• Inventors: Kippenberg, Tobias, Schliesser, Albert, Del 'Haye, Pascal
• Granted Patent: US 7,982,944 B2
• Time in Patent Office: Days
• US Class Current: 372/32
• CPC Class Codes: G02F 1/39 for parametric generation or amplification of light, infrared or ultraviolet waves
• CPC Class Codes: G02F 2203/15 involving resonance effects, e.g. resonantly enhanced interaction
• CPC Class Codes: G02F 2203/54 Optical pulse train (comb) synthesizer
• CPC Class Codes: G02F 2203/56 Frequency comb synthesizer
• CPC Class Codes: H04B 10/506 Multiwavelength transmitters

Abstract

An optical frequency comb generator includes a laser device arranged for generating input laser light having a predetermined input light frequency, a dielectric micro-resonator having a cavity exhibiting a third order nonlinearity, so that the micro-resonator is capable of optical parametric generation providing parametrically generated light, and a waveguide optically coupled to the micro-resonator, the waveguide being arranged for in-coupling the input laser light into the micro-resonator and out-coupling the parametrically generated light out of the micro-resonator, wherein the laser device, the waveguide and the micro-resonator being arranged for resonantly in-coupling the laser input light to a mode of the micro-resonator with a minimum power level so that an optical field inside the cavity exceeds a predetermined cascaded parametric oscillation threshold at which the parametrically generated light includes frequencies of frequency sidebands of the input light frequency and of the sidebands thereof.

Claims

1. An optical frequency comb generator, comprising:

a laser device arranged for generating input laser light having a predetermined input light frequency,

a dielectric micro-resonator having a cavity exhibiting a third order nonlinearity, so that the micro-resonator is capable of optical parametric generation providing parametrically generated light, and

a waveguide optically coupled to the micro-resonator, the waveguide being arranged for in-coupling the input laser light into the micro-resonator and out-coupling the parametrically generated light out of the micro-resonator,

wherein the laser device, the waveguide and the micro-resonator are arranged for resonantly in-coupling the laser input light to a mode of the micro-resonator with a minimum power level so that an optical field inside the cavity exceeds a predetermined cascaded parametric oscillation threshold at which the parametrically generated light includes frequencies of frequency sidebands of the input light frequency and of the sidebands thereof.

2. The optical frequency comb generator according to claim 1, wherein the laser device, the waveguide and the micro-resonator are arranged so that an optical field inside the cavity exceeds a predetermined cascaded parametric oscillation threshold at which the parametrically generated light includes frequencies of at least 10 frequency sidebands relative to the input light frequency.

3. The optical frequency comb generator according to claim 1, wherein the micro-resonator is adapted for exhibiting high-Q modes characterized by a photon lifetime in excess of 10 nanoseconds.

4. The optical frequency comb generator according to claim 1, further comprising a substrate containing the micro-resonator and the waveguide.

5. The optical frequency comb generator according to claim 4, wherein the waveguide is a rectangular waveguide arranged on the substrate.

6. The optical frequency comb generator according to claim 1, wherein the micro-resonator is compensated for a dispersion thereof.

7. The optical frequency comb generator according to claim 1, further comprising a detector device arranged for detecting the parametrically generated light.

8. The optical frequency comb generator according to claim 7, further comprising a feedback loop coupled with the detector device, wherein a repetition rate, defined as spacing between adjacent comb modes, is detected and stabilized using the feedback loop controlling intrinsic properties of at least one of the laser device, the waveguide and the micro-resonator.

9. The optical frequency comb generator according to claim 8, wherein the feedback loop is arranged for controlling at least one of temperature of the micro-resonator, strain on the micro-resonator, pump power of the input laser device, laser frequency of the input laser device and distance between waveguide and micro-resonator.

10. The optical frequency comb generator according to claim 1, wherein the laser device is a stabilized continuous wave laser.

11. The optical frequency comb generator according to claim 1, wherein the micro-resonator has a diameter of less than 1 mm.

12. The optical frequency comb generator according to claim 1, wherein the laser device, the waveguide and the micro-resonator are arranged for generating optical pulses with a repetition rate given by an integer multiple of a free spectral range of the micro-resonator.

13. The optical frequency comb generator according to claim 1, wherein the micro-resonator contains light at an intensity of more than 1 Gigawatt per square centimeter.

14. The optical frequency comb generator according to claim 1, further comprising a phase and/or amplitude manipulation device arranged to individually manipulate a phase and/or an amplitude of parametrically generated comb components.

15. The optical frequency comb generator according to claim 1, further comprising a compression device arranged for compression of light pulses to Fourier limit and/or spectral flattening.

16. The optical frequency comb generator according to claim 1, further comprising a modulator device arranged to individually modulate a phase and/or an amplitude of parametrically generated comb components.

17. The optical frequency comb generator according to claim 16, wherein the modulator device is arranged to modulate modulated comb components as carriers for data transmission.

18. The optical frequency comb generator according to claim 1, wherein the laser device, the waveguide and the micro-resonator are arranged for generating the parametrically generated light by four-wave-mixing.

19. The optical frequency comb generator according to claim 1, wherein the laser device, the waveguide and the micro-resonator are arranged for generating the parametrically generated light with phase-coherent frequency sidebands of first and higher order.

20. The optical frequency comb generator according to claim 1, wherein the laser device, the waveguide and the micro-resonator are arranged for generating the parametrically generated light such that amplitudes of neighboring frequency sidebands of first and higher order have a variation smaller than 3 db.

21. The optical frequency comb generator according to claim 1, wherein an out-coupling rate of the parametrically generated light from the micro-resonator to the waveguide is not smaller than 1/10 of an intrinsic lost rate within the resonator.

22. The optical frequency comb generator according to claim 1, including at least one of the following features:

the waveguide includes a prism or a tapered optical fiber,

the waveguide is made from silicon or silicon nitride,

the micro-resonator is a whispering gallery mode micro-resonator,

the micro-resonator has a non-circular shape,

the micro-resonator has a circular shape,

the micro-resonator has a disk shape or a ring shape,

the micro-resonator is made from at least one of silicon, silicon nitride, calcium fluoride, silica and plastic, and

the micro-resonator is doped with a nonlinear material exhibiting a third order nonlinearity.

23. The optical frequency comb generator according to claim 22, wherein the micro-resonator is made from silicon on insulator wafer material.

24. A method of generating an optical frequency comb, comprising the steps of:

generating input laser light with a laser device, said input laser light having a predetermined input light frequency,

coupling the input laser light via a waveguide into a dielectric micro-resonator having a cavity exhibiting a third order nonlinearity,

providing parametrically generated light in the micro-resonator by optical parametric generation, wherein the laser input light is coupled to a mode of the micro-resonator with a minimum power level so that an optical field inside the cavity exceeds a predetermined cascaded parametric oscillation threshold at which the parametrically generated light includes frequencies of frequency sidebands of the input light frequency and of the sidebands thereof, and

coupling the parametrically generated light out of the micro-resonator.

25. The method according to claim 24, wherein the optical field inside the cavity exceeds a predetermined cascaded parametric oscillation threshold at which the parametrically generated light includes frequencies of at least 10 frequency sidebands relative to the input light frequency.

26. The method according to claim 24, comprising the step of compensating the micro-resonator for a dispersion thereof.

27. The method according to claim 24, comprising the step of detecting the parametrically generated light with a detector device.

28. The method according to claim 27, comprising the steps of detecting and stabilizing a repetition rate using a feedback loop being coupled with the detector device being arranged for controlling intrinsic properties of at least one of the laser device, the waveguide and the micro-resonator.

29. The method according to claim 28, comprising the step of controlling at least one of temperature of the micro-resonator, strain on the micro-resonator, pump power of the input laser device, laser frequency of the input laser device and distance between waveguide and micro-resonator using the feedback loop.

30. The method according to claim 24, comprising the step of generating optical pulses with a repetition rate given by an integer multiple of a free spectral range of the micro-resonator.

31. The method according to claim 24, wherein the input laser light is coupled into the micro-resonator such that the micro-resonator contains light at an intensity of more than 1 Gigawatt per square centimeter.