Demodulation method for composite modulation caused by dynamic optical path in FSI optical frequency tuning

The single-source frequency scanning interferometry (FSI) system does not have the ability to directly measure the dynamic optical path in principle, as it cannot directly distinguish between the frequency components introduced by a change in the dynamic optical path. To address the phase modulation problem introduced by both time-domain optical frequency modulation and time-domain optical path modulation in FSI dynamic measurement, we propose a decoupling method based on time-frequency analysis, which combines the variable convolution kernel Morlet wavelets (VCKMW) method with an adaptive optimal estimation method that can determine different motion modes, to realize the dynamic optical path measurement capability of FSI. Without any improvement in hardware, the proposed method could measure dual moving targets and recognize different motion modes. The feasibility of the proposed method was verified experimentally.