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.

The multiple pulse train interference (MPTI) ranging system takes advantage of the high accuracy and absolute length measurement capability, but traditional scheme has a large measurement dead zone. In this Letter, we propose a MPTI ranging scheme based on chip-based soliton microcomb to achieve high-precision but no dead-zone measurement. The measurement optical path is improved to solve the problem of cross correlation interference fringe overlap, and a peak fitting algorithm is employed to further improve the measurement accuracy of the system. Using a commercial He–Ne interferometer, a 384 nm precision is obtained in 1.5 m distance measurements. Advantages of the simple optical path, high precision, and no measurement dead zone are expected to realize on-chip integration and provide a solution for precision measurement.

We demonstrate an arbitrary distance measurement method by chirped pulse spectrally interferometry (CPSI) using femtosecond optical frequency comb (OFC). In this paper, the chirped fiber Bragg grating (CFBG) is used to investigate the mapping relationship between displacement and the center frequency of the chirped spectral interferogram. We overcome the direction ambiguity of dispersive interferometry (DPI) ranging and expand the range of distance measurement to 18 cm. Besides, we achieve a full range of dead-zone free ranging by introducing a variable optical delay line (VODL). And through principles simulation and experiment, it is demonstrated that the measurement accuracy is 12 µm in comparison with an incremental He–Ne laser interferometer and the minimum Allen deviation is 52 nm at an average time of 1.76 ms. Similarly, in the experiment with long-distance of ∼30m, the accuracy reaches 20 µm, and 2.51 µm repeatability is achieved under harsh environment.

Absorption spectroscopy based on frequency-modulated continuous-wave (FMCW) technology is characterized by a wide measuring range, high detection sensitivity, and high sensing speed. These features enable sensing of multiple target points, and continuous real-time gas monitoring. In this article, an on-chip FMCW multichannel absorption spectrometer is designed for the simultaneous measurement of optical path and gas absorption spectra. The wide tuning range of FMCW facilitates the measurement of multiple absorption bands of gas molecules under test. Based on the characteristics of frequency division multiplexing, the gas absorption spectra corresponding to different points can be detected simultaneously. Frequency modulation nonlinearity is corrected by introducing an auxiliary interference optical path with a fixed delay of 4 m, and the dual-interference optical path of the system is integrated into a silicon chip. Three-way parallel sensing experiments are carried out to demonstrate the efficacy of the proposed spectrometer. The results show that the coherent average measurement accuracy of gas absorption peak wavelength is better than 0.002 nm, and the optical path measurement accuracy is better than 25 μm. The system offers several advantages such as excellent integrability, wide band operation, high precision and multichannel synchronous online measurement. Due to these features, this system has high practical value in the field of gas sensing.

Integration of whispering-gallery-mode (WGM) resonators with high-quality factors (Q) into advanced timing, oscillator, and sensing systems demands a platform that enables precise resonance frequency modulation. This study investigates the tuning characteristics of magnetorheological polydimethylsiloxane (MR-PDMS) coated microspheres (µ-spheres) employed as magnetic microresonators, achieving a Q value of 10⁷ at the 1550 nm wavelength. Magnetic WGM resonators not only endow the device with magnetic adjustability but also markedly improve thermal resistance. Experimental findings reveal that the magnetic µ-sphere demonstrates a sensitivity of −32.53 MHz/mT, outperforming conventional magnetic WGM resonators. Furthermore, analysis of the temperature dependence shows a reduction in fluctuation to −2.85 MHz/K, thereby greatly enhancing the sensor’s practical detection limit.