Dissipative Kerr soliton (DKS) microcombs based on multi-mode Si3N4 waveguides turn into an ideal tool that is compact and has precision for optical communication, precision spectroscopy, and frequency metrology. However, spatial waveguide mode interaction leads to local disturbances of dispersion, which may hinder DKS microcombs formation. In this letter, we generate the DKS microcomb in a dual-mode interaction Si3N4 microresonator without suppressing spatial waveguide mode interaction. The spatial waveguide mode interaction is investigated in the dual-mode interaction Si3N4 microresonator with a cross-sectional area of 800 × 1700 nm2. DKS microcomb is deterministically generated in the microresonator using an auxiliary light heating method. Furthermore, an integrated microcomb frequency measurement system is designed based on the DKS microcomb for frequency metrology.

Since the dispersive interferometry (DPI) based on optical frequency combs (OFCs) was proposed, it has been widely used in absolute distance measurements with long-distance and high precision. However, it has a serious problem for the traditional DPI based on the mode-locked OFC. The error of measurements caused by using the fast Fourier transform (FFT) algorithm to process signals cannot be overcome, which is due to the non-uniform sampling intervals in the frequency domain of spectrometers. Therefore, in this paper, we propose a new mathematical model with a simple form of OFC to simulate and analyze various properties of the OFC and the principle of DPI. Moreover, we carry out an experimental verification, in which we adopt the Lomb–Scargle algorithm to improve the accuracy of measurements of DPI. The results show that the Lomb–Scargle algorithm can effectively reduce the error caused by the resolution, and the error of absolute distance measurement is less than 12 μm in the distance of 70 m based on the mode-locked OFC.

In-plane micro-displacement measurement is a critical requirement in many engineering fields. In this work, we present a measurement system based on pixelated metasurface to achieve high-precision, absolute in-plane micro-displacement measurement within limited measurement space. By exploiting the wavelength selectivity of pixelated metasurface, the composite frequency light source is reflected to the camera, forming images containing features. Subsequently, a displacement ruler is established to obtain linear displacement values. The designed device achieves resolution as low as sub-micrometer levels for in-plane micro-displacement, with measurement errors within 0.5 and 1.3 μm for single-step displacements of 10 and 5 μm, respectively. The measurement scheme also exhibits good measurement stability over extended durations. The proposed scheme achieves absolute correspondence between displacement and reference values through visual images, and the system operates within a very small working volume. Therefore, it holds promise for application in engineering scenarios where absolute traceability of the target position is required and the measurement space is limited.