Multi-Channel Vibration Measurements Based on a Self-Mixing Vertical-Cavity Surface-Emitting Laser Array

This paper studied a multi-channel self-mixing interferometric vibration measurement system based on a vertical-cavity surface-emitting laser array. A 1 × 8 laser array was utilized to irradiate multiple positions of a vibrating target to establish independent measurement channels. The reflected light beams, carrying the vibration information of each position, were redirected back into the laser and coherently mixed with the original optical field, generating the self-mixing interference. The interferometric signals were measured by monitoring the junction voltage variations across the terminals of the VCSEL array. A denoising filtering method based on the variational mode decomposition with Hausdorff distance was proposed to improve the signal-to-noise ratio. Furthermore, the vibration waveforms of different positions were reconstructed using the Hilbert transform-based orthogonal phase demodulation technology. Both simulations on synthetic signals and experiments with real datasets were conducted to validate the feasibility and stability of the proposed method. Due to the array detection configuration, the system boasted a simple and compact structure, low power consumption, and easy extensibility, laying the groundwork for high accuracy and multi-dimensional vibration detection in industrial applications.