Chip-scale frequency-comb assisted coherent lidar ranging with sub-micrometer precision

1. A system for soliton microcomb-based precision dimensional metrology via spectrally-resolved interferometry, comprising:

a dual-pumped soliton microcomb generator comprising a pump, a microresonator, and

an auxiliary pump and that generates a single-soliton microcomb;

an erbium-doped fiber amplifier (EDFA) that amplifies a C-band section of the soliton microcomb;

a non-polarizing beam splitter (BS) that divides the soliton microcomb pulses into a reference arm pulse and a measurement arm pulse for an interferometer and recombines the reference arm pulse and the measurement arm pulse into a recombined beam upon their return;

a free-space collimator lens (CL);

a reference mirror (M REF ); and

a measurement mirror (M MEA ).

2. The system of claim 1 , wherein the microresonator is a planar waveguide Si 3 N 4 microresonator, wherein a width of the microresonator is adiabatically varied to tune dispersion and improve single-mode mode locking.

3. The system of claim 1 , wherein the measurement mirror (M MEA ) is mounted on a motorized stage for translation motion on a measurement path.

4. The system of claim 1 , wherein the pump laser is set to generate the single-soliton state with counter-clockwise propagation in the microresonator and the auxiliary pump laser wavelength is set for blue-detuning to thermally stabilize the microresonator with clockwise propagation.

5. The system of claim 1 , wherein the recombined beam is collimated into a single-mode fiber and sent to an optical spectrum analyzer.

6. The system of claim 4 , wherein the optical spectrum analyzer reads out a tooth-resolved and high-visibility interferogram.

7. The system of claim 1 , wherein the C-band section ranges from 1530 nm to 1565 nm.

8. The system of claim 1 , wherein the non-polarizing beam splitter is a non-polarizing beam splitter with 50:50 dividing ratio that divides an 88.5 GHz soliton microcomb.

9. The system of claim 1 , wherein the soliton microcomb has a large free-spectral range of 88.5 GHz.

10. The system of claim 1 , further comprising using homodyne interferometry to improve the distance metrology precision.

11. A method for soliton microcomb-based precision dimensional metrology via spectrally-resolved interferometry, comprising:

generating a single-soliton microcomb using a dual-pumped soliton microcomb generator comprising a TE pump, a microresonator, and an TM auxiliary pump;

amplifying a C-band section of the soliton microcomb using an erbium-doped fiber amplifier (EDFA);

dividing, using a non-polarizing beam splitter (BS), the soliton microcomb pulses into a reference arm pulse and a measurement arm pulse for an interferometer and recombining the reference arm pulse and the measurement arm pulse into a recombined beam upon their return.

12. The method of claim 10 , wherein the microresonator is a planar waveguide Si 3 N 4 microresonator, wherein a width of the microresonator is adiabatically varied to tune dispersion and improve single-mode mode locking.

13. The method of claim 10 , wherein the measurement mirror (M MEA ) is mounted on a motorized stage for translation motion on a measurement path.

14. The method of claim 10 , wherein the TE pump laser is set to generate the single-soliton state with counter-clockwise propagation in the microresonator and the TM auxiliary laser wavelength is set for blue-detuning to thermally stabilize the microresonator with clockwise propagation.

15. The method of claim 10 , wherein the recombined beam is collimated into a single-mode fiber and sent to an optical spectrum analyzer.