High Resolution Laser Self-Mixing Displacement Sensor Under Large Variation in Optical Feedback and Speckle

Saqib Amin (1) , Usman Zabit (1, 2) , Olivier D Bernal (3, 4) , Tassadaq Hussain (1)

1 Riphah International University
2 NUST - National University of Sciences and Technology [Islamabad]
3 ENSEEIHT - Ecole Nationale Supérieure d'Electrotechnique, d'Electronique, d'Informatique, d'Hydraulique et de Télécommunications
4 LAAS-OASIS - Equipe Capteurs optiques et systèmes intégrés intelligents

Self-Mixing interferometry (SMI) signal characteristics are highly dependent on both the operating optical regime and target surface. In this paper, a method is proposed to overcome some identified limitations of the even power scalable algorithm (EPSA) [1], such as the required operating regime to be weak feedback. In addition, by using the up-sampling techniques, the number of stages involved in the even-power scalable algorithm can be drastically increased without any data acquisition bandwidth modification. Here, 10 successive stages have been successfully implemented to achieve a theoretical resolution of λ0/2 13. It is further shown that the proposed method can handle and process weak, moderate and strong feedback regime as well as speckle affected SMI signals more efficiently. Lastly, FPGA based hardware emulation of EPSA is also done for later embedded implementation of this high-resolution algorithm. FPGA synthesis results show that the designed system can measure maximum target velocity up to 1.18 m/s while consuming total power of 1.4W.

Mots clés: Self-mixing; Signal processing; Speckle

Domaines: Optique / photonique

Saqib Amin, Usman Zabit, Olivier D Bernal, Tassadaq Hussain. High Resolution Laser Self-Mixing Displacement Sensor Under Large Variation in Optical Feedback and Speckle. IEEE Sensors Journal, 2020, 20 (16), pp.9140-9147. ⟨10.1109/JSEN.2020.2988851⟩. ⟨hal-02959434⟩