Laser-based light detection and ranging (lidar) plays a significant role in both scientific and industrial areas. However, it is difficult for existing lidars to achieve high speed, high precision, and long distance simultaneously. Here, we demonstrate a high-performance lidar based on a chip-scaled soliton microcomb (SMC) that can realize all three specialties simultaneously. Aided by the excellent properties of ultrahigh repetition rate and the smooth envelope of the SMC, traditional optical frequency comb (OFC)-based dispersive interferometry is heavily improved and the measuring dead zone induced by the mismatch between the repetition rate of the OFC and resolution of the optical spectrum analyzer is totally eliminated. Combined with an auxiliary dual-frequency phase-modulated laser range finder, the none-dead-zone measurable range ambiguity is extended up to 1500 m. The proposed SMC lidar is experimentally implemented in both indoor and outdoor environment. In the outdoor baseline field, real-time, high-speed (up to 35 kHz) measurement of a long distance of ∼ 1179 m is achieved with a minimum Allan deviation of 5.6 μm at an average time of 0.2 ms (27 nm at an average time of 1.8 s after high-pass filtering). The present SMC lidar approaches a compact, fast, high-precision, and none-dead zone long-distance ranging system, aimed at emerging applications of frontier basic scientific research and advances in industrial manufacturing.

Laser-based light detection and ranging (LIDAR) offers a powerful tool to real-timely map spatial information with exceptional accuracy and owns various applications ranging from industrial manufacturing, and remote sensing, to airborne and in-vehicle missions. Over the past two decades, the rapid advancements of optical frequency combs have ushered in a new era for LIDAR, promoting measurement precision to quantum noise limited level. For comb LIDAR systems, to further improve the comprehensive performances and reconcile inherent conflicts between speed, accuracy, and ambiguity range, innovative demodulation strategies become crucial. Here we report a dispersive Fourier transform (DFT) based LIDAR method utilizing phase-locked Vernier dual soliton laser combs. We demonstrate that after in-line pulse stretching, the delay of the flying pulses can be identified via the DFT-based spectral interferometry instead of temporal interferometry or pulse reconstruction. This enables absolute distance measurements with precision starting from 262 nm in single shot, to 2.8 nm after averaging 1.5 ms, in a non-ambiguity range over 1.7 km. Furthermore, our DFT-based LIDAR method distinctly demonstrates an ability to completely eliminate dead zones. Such an integration of frequency-resolved ultrafast analysis and dual-comb ranging technology may pave a way for the design of future LIDAR systems.

For ultrasonic systems, the resonance frequency tracking (RFT) is the most critical step. The rapid development in advanced material processing and microelectronics package has increased the demand of high speed RFT. Therefore, this paper proposes a fast RFT (FRFT) method according to the characteristics of piezoelectric transducers' (PT) admittance circle. In the proposed method, the PT is driven at two different frequencies, and the PT's admittance is collected and calibrated. Then, the PT's mechanical resonance frequency is derived using the admittance information after calibration. The proposed method is not affected by the parallel capacitor and the matching circuit. Additionally, the optimal initial values of the involved parameters are determined in order to improve the accuracy of the proposed method. Furthermore, an improved method based on multiple tracking is also provided. Simulations and experiments demonstrate that using the proposed FRFT method, the ultrasonic system can track the resonance frequency in a short time with high accuracy.

Traditional frequency modulated continuous wave (FMCW) LIDAR ranging is based on heterodyne detection, calculating unknown distance by extracting the frequency of the interference signal, while the main error source is frequency modulation (FM) nonlinearity. In this paper, a ranging system based on a microresonator soliton comb is demonstrated to correct the nonlinearity by sampling the ranging signals at equal frequency intervals, producing a ranging error lower than 20 µm, while at the range of 2 m. Advantages of fast data acquisition, light computation requirements, and a simple optical path, without long optical fiber, give this method a high practical value in precision manufacturing.

A universal method is proposed for fast tracking the peak wavelength of a fiber Bragg grating (FBG) reflection spectrum, which is the essential procedure of most FBG interrogators. Assuming the FBG reflection spectrum is sampled uniformly, we decompose the Moore–Penrose of the coefficient matrix into a formula that only contains a division and a dozen additions and multiplications; thereby, the cost of computation can be greatly reduced. Based on the analysis of the characteristics of the error introduced by the spectrum’s nonlinearity, we found and defined an error associated with the distance between the sampled peak and actual peak, and the compensating method for the error is also given. After compensation, the proposed method can speed up the tracking process 10 times or more without sacrificing the accuracy. An economical FBG interrogator with a commercial field programmable gate array (FPGA) and a microspectrometer was built up to verify the method, which was able to achieve a measurement frequency of 17 kHz.

Soliton microcombs offer unprecedented laser sources for high-precision ranging due to their merits of high repetition rate, excellent coherence, and compact size. However, high repetition rate limits the nonambiguity range (NAR) of ranging. Previous dual-comb–based methods can extend the NAR, but asynchronous measurement error (AME) is commonly introduced, which greatly limits the ranging accuracy. Here, we propose a cross dual-microcomb absolute ranging scheme based on dispersion-interferometry method. The AME introduced during dynamic measurement is completely eliminated by one-shot spectral sampling, while the NAR is extended from 3 millimeters to 339 meters by Vernier effect when the repetition-rate jitter is 2 hertz. In addition, the excellent system performance has been verified at different distances and the Allan deviation down to 5.63 nanometers after averaging 56 seconds. Our scheme boasts the potential of straightforward chip architecture and minimal detector requirements and provides an advanced method for future high-precision long-distance ranging and miniaturized lidar systems.