Simulation and error analysis of a laser feedback interference system based on phase-freezing technology

Based on laser feedback interferometry (LFI) combined with phasefreezing technology (PFT), a micro displacement measurement system is demonstrated. A phase modulator is added to modulate the external cavity phase, and the PFT is used for sampling and demodulation; thus, the displacement information of the external target is reconstructed. The signal modulation, sampling, reconstruction technology is researched and its feasibility is proved by simulation. The results of error analysis show that the measurement accuracy is affected by the modulation frequency, the sampling frequency and the target vibration frequency.