1.5 μm LFMCW-Laser heterodyne measurement with ultra-precision for the glass thickness

We proposed a method of LFMCW-Laser heterodyne measurement for the glass thickness with ultra-precision, and designed the measurement scheme and analyzed the heterodyne measurement principle. We also analyzed the feasibility, measurement accuracy and SNR of this method by simulation and come to conclusion that increasing the frequency modulation rate can improve SNR and measurement precision. Then we simulated the measurement of the glass plates with different thicknesses. The measurement results showed that the relative error of LFMCW-Laser heterodyne measurement with ultra-precision for the glass thickness was less than 0.2%.