Vibration reconstruction and optical feedback parameter evaluation based on the direction discrimination in self-mixing interferometry.

Laser diode-based self-mixing interferometry (SMI) is a promising technique for noncontact sensing and its industry. In this paper, a phase unwrapping method in the several optical feedback levels is proposed based on displacement direction. A novel, to the best of our knowledge, method for evaluating the optical feedback factor C simultaneously with the linewidth enhancement is proposed by taking into account the effect of the accuracy of the linewidth enhancement $ \alpha $ on the evaluated method for C based on the differential feature of vibration reconstruction signal.

Evaluation method for the optical feedback factor and linewidth enhancement factor using phase discontinuities in self-mixing interferometry signals.

Self-mixing interferometry (SMI) is a reliable method that has been applied to measuring displacements, absolute distances, and velocities of remote targets. Evaluating the optical feedback factor and the linewidth enhancement factor is a vital step in calculating laser diode parameters and in processing SMI signals using phase unwrapping. This paper proposes an evaluation method for the optical feedback factor and the linewidth enhancement factor of arbitrary waveforms by investigating the slopes of phase discontinuity distribution in the optical feedback regime of 1<.