High-Precision Silicon-Integrated Frequency-Modulated Continuous Wave LiDAR Calibrated Using a Microresonator

Abstract

Frequency-modulated continuous wave (FMCW) LiDAR can achieve long-distance and high-precision measurement, and the ranging error mainly comes from the nonlinearity of the laser frequency sweep. In this study, a high-precision silicon-integrated FMCW LiDAR is proposed. An equal frequency hypercube network is established by the stable free spectral range (FSR) of the microresonator to calibrate the nonlinearity of FMCW, and the distance matrix is obtained by analyzing the phase difference matrix of the FMCW signal. A standard length-based microresonator FSR calibration scheme is used to further improve the LiDAR accuracy. The feasibility of the scheme is verified by ranging and three-dimensional (3D) imaging. The ranging is carried out indoors and outdoors. In the indoor environment of a distance of 4 m, the minimum Allan deviation is 65 nm at 10.24 s. In the outdoor environment, the minimum Allan deviation at 438 m is 420 nm at 10.24 s. The 3D imaging can reconstruct the spatial point cloud of the objects and identify the spatial targets. This scheme has good on-chip integration capability and can be further combined with lens-assisted beam steering and optical phased array, laying the foundation for compact, large bandwidth, long-range, and high-precision LiDAR.

Frequency-swept feedback interferometry for noncooperative-target ranging with a stand-off distance of several hundred meters

“…To avoid device damage, the frequency of the triangular wave is less than 100 Hz. Overall, the swept frequency of the system is less than 60 Hz, comparable with other reported research with mechanical modulation, such as motor-based externalcavity-tunable diode lasers [49,50]. Consequently, the usage of mechanical modulation in our system makes the ranging rate slower than electrical modulation for laser diodes (LDs).…”

Microcavity Raman Laser-Based FMCW LiDAR with Enhanced Echo Sensitivity

“…This challenge is attributed to the measuring rates being dictated by the sweeping period, which is constrained by the thermal cycling response of the microcavity. As a result, the swept frequency of the system remains below 100 Hz, a range that aligns with other reported research utilizing the mechanical modulation methods. , Another limitation is the temperature tuning technique employed in the WGM resonators. In this approach, the achievable tuning range is constrained to tens of GHz, and the tuning process is slow.…”

“…Frequency-modulated continuous-wave laser detection and ranging (FMCW LiDAR) holds capability to accurately measure the absolute distance to diffuse reflectors at large standoff distances, owing to its technical advantages such as high precision, large dynamic range, anti-interference capability, and high signal-to-noise ratio (SNR). − This coherent detection principle is more robust to environmental variables and phase noise than other conventional LiDAR technologies, such as time-of-flight and amplitude-modulated continuous-wave LiDAR. − As such, FMCW LiDAR systems have demonstrated great potential for various applications in aerospace, autonomous driving, three-precision manufacturing, and many other fields. − …”

“…used a soliton microcomb to enable multichannel parallel ranging and increase the measurement rate . Jihui Zheng et al proposed a high-precision silicon-integrated FMCW LiDAR, and a microresonator FSR calibration scheme is employed to further enhance accuracy . Notably, one major constraint of current LiDAR systems lies in their echo-signal sensitivity.…”

High-Speed Optical Fiber Communication in China

“…The electro-optical modulator is the core device of a DCI system. Chinese scientists have conducted research in this area for many years, especially in thin-film LiNbO3, which has made great progress. − We will summarize the progress on this topic. Cost is a core consideration in a DCI system.…”