A microcomb-empowered Fourier domain mode-locked LiDAR

TL;DR

This paper introduces a high-precision, high-speed FMCW LiDAR system using a Fourier domain mode-locked laser combined with a silicon nitride microcomb, achieving sub-10 nm spatial resolution and rapid 24.6 kHz update rate.

Contribution

It demonstrates the integration of a microcomb with an FDML laser to significantly enhance LiDAR update rate and precision, addressing nonlinear frequency sweep challenges.

Findings

Achieved sub-10 nm spatial precision in LiDAR.

Realized a 24.6 kHz update rate for rapid sensing.

Velocity measurement uncertainty below 0.4 mm/s.

Abstract

Light detection and ranging (LiDAR) has emerged as an indispensable tool in autonomous technology. Among its various techniques, frequency modulated continuous wave (FMCW) LiDAR stands out due to its capability to operate with ultralow return power, immunity to unwanted light, and simultaneous acquisition of distance and velocity. However, achieving a rapid update rate with sub-micron precision remains a challenge for FMCW LiDARs. Here, we present such a LiDAR with a sub-10 nm precision and a 24.6 kHz update rate by combining a broadband Fourier domain mode-locked (FDML) laser with a silicon nitride soliton microcomb. An ultrahigh frequency chirp rate up to 320 PHz/s is linearized by a 50 GHz microcomb to reach this performance. Our theoretical analysis also contributes to resolving the challenge of FMCW velocity measurements with nonlinear frequency sweeps and enables us to realize velocity measurement with an uncertainty below 0.4 mm/s. Our work shows how nanophotonic microcombs can unlock the potential of ultrafast frequency sweeping lasers for applications including LiDAR, optical coherence tomography and sensing.