Going the distance with dual-chirped-comb LiDAR

Laser-based light detection and ranging (LiDAR) technology measures the time it takes for laser light to return from a target to determine how far away it is. It’s used to make long range measurements in both science and industry, including in autonomous vehicles and remote sensing. The conventionally used dual-comb ranging LiDAR method makes precise measurements by comparing two laser sources. However, avoiding a type of signal distortion known as spectral aliasing creates a trade-off between the speed and precision of measurements made with this technique.

Xu et al. discussed how dual-chirped comb interferometry, an emerging technology, can overcome the limitations of dual-comb ranging. The dual-chirped-comb method integrates the time stretch dispersive Fourier transform of the spectral interference signal. This mathematical technique allowed the spectrum of laser light to be analyzed in real-time, increasing measurement speed without sacrificing precision.

The authors highlighted recent breakthroughs related to dual-chirped-comb interferometry, which show the technique also extends the maximum measurement distance. To help guide newcomers to the field, they explain the fundamental principles underlying these innovations and bridge the technique’s theory to its real-world applications.

“This technique can provide new inspiration for comb-ranging researchers to help advance interferometric measurement technologies,” said author Liang Xu. “We hope this review inspires the adoption of dual-chirped comb architectures in dynamic industrial monitoring, such as rotor-stator gap tracking, or LiDAR systems.”

The authors also considered future improvements to dual-chirped-comb interferometry systems and new applications.

“We propose transformative pathways, including acoustic sensing and chip-scale miniaturization, thereby establishing a roadmap for high-speed and dynamic measurement systems in scientific and industrial scenarios,” Xu said.

Source: “A review of dual-chirped-comb interferometry for fast long-distance ranging,” by Liang Xu, Chen Liu, Liao Chen, Chi Zhang, and Xinliang Zhang, APL Photonics (2025). The article can be accessed at https://doi.org/10.1063/5.0241325 .