Dual-comb sensing of hand gesture by wearable FBG arrays demodulation based on a free-running mode-locked fiber laser

This paper introduces a rapid and accurate wearable hand gesture sensing approach with optical fiber Bragg grating (FBG) arrays, interrogated by the dual-comb spectroscopy (DCS) technique. By leveraging the asynchronous optical sampling (ASOPS) method, rapid and high-resolution dynamic hand gesture sensing can be achieved. This is facilitated by utilizing a single-cavity dual-comb FBG array demodulation scheme in real-time to monitor single-shot FBG's reflective spectrum, resulting from each finger movement in hand gestures. The proposed sensing system offers a high sensitivity of ∼5 pm/degree, and captures the gesture changes at a refresh rate of ∼2 kHz. Furthermore, a series of measurements was conducted to assess the response characteristics and the effectiveness of the FBG-based dual-comb hand gesture sensing system in capturing dynamic gestures. The system maintains a root mean square error (RMSE) accuracy of better than 1.9 degrees in finger joint measurements, corresponding to a spectral resolution of ∼9.6 pm in single-shot wavelength shifts. The results demonstrate that the capabilities of picometer-level resolution at kilohertz-level measurement speeds could highlight the potential of the FBG-based dual-comb sensing system for high-speed, high-resolution hand motion sensing, with significance for applications such as robotic gesture recognition and human-machine interaction.