Asin Phase Demodulation for High-Resolution FMCW Interferometry

Frequency-modulated continuous-wave (FMCW) interferometry is a pivotal technique for high-resolution, noncontact distance measurement. However, enhancing its resolution typically requires a substantial laser tuning range, and a systematic framework linking signal quality to ultimate resolution remains underdeveloped. This article introduces an Arcsine (Asin) phase demodulation method based on peak feature reconstruction to achieve high-resolution FMCW interferometry with a relatively compact tuning range. The proposed method reconstructs the phase via peak detection and an arcsine operation, significantly improving the accuracy of demodulation per unit tuning range. Experimental validation demonstrates that with a tuning range of only 26 GHz, our approach enables absolute distance measurement over 0-1 m with submicrometer resolution and an accuracy of 0.86μ m.