A laser self-mixing interference vibrometer based on current modulation and DSP demodulation

Abstract

The modulation and demodulation technique of laser self-mixing interference vibrometer is researched in this paper.Combining with triangular current modulation and DSP demodulation technique, a new-type laser self-mixing interference vibrometer is designed to achieve non-contact vibration measurement of a target. Theoretical analysis, simulation results and error evaluation are presented in this paper. The vibration waveform is reconstructed with an accuracy of 0.325 micron in a wide dynamic range. Experiments results show a good agreement with the simulative results. The vibrometer is compact, inexpensive, self-aligning and can be applied to various vibration measurements for its simplicity.