Dual-Parameter Correction Method for Dispersion Compensation in Polarized Low-Coherence Interferometry with High Accuracy

A dual-parameter compensation method focusing on spatial frequency and spatial phase is proposed to enhance the demodulation precision of a polarized low-coherence interferometry system based on the white LED. The dual-parameter compensation method for spatial frequency and spatial phase was identified by establishing a model relating spatial frequency, spatial phase, and cavity length. For the first time, we have effectively compensated for the spatial phase variations in low-coherence interference fringes caused by dispersion effects, thereby overcoming the long-standing issue of nonlinearity between spatial frequency and spatial phase due to dispersion. This method has also thoroughly resolved the problem of interference order jumps, a critical challenge in the field. The method's efficacy was confirmed through pressure experiments within a 250 kPa range, where it demonstrated a significant improvement in demodulation accuracy of interference fringes. Notably, the demodulation error was reduced to less than 0.077 kPa, marking a twenty-two-fold increase in precision.