Vibration reconstruction and optical feedback parameter evaluation based on the direction discrimination in...

Area of Science:

• Optics and Photonics
• Laser Physics
• Metrology

Background:

• Self-mixing interferometry (SMI) using laser diodes is valuable for noncontact sensing.
• Accurate evaluation of optical feedback and linewidth enhancement is crucial for SMI precision.
• Existing methods face challenges in simultaneously determining these parameters under varying feedback levels.

Purpose of the Study:

• To propose a novel phase unwrapping method for laser diode SMI based on displacement direction.
• To develop a new technique for simultaneously evaluating the optical feedback factor (C) and linewidth enhancement factor ($ \alpha $).
• To assess the impact of linewidth enhancement accuracy on the optical feedback factor evaluation.

Main Methods:

• A phase unwrapping algorithm is developed, considering different optical feedback regimes.
• A novel method is presented to determine the optical feedback factor (C) and linewidth enhancement ($ \alpha $) concurrently.
• The method utilizes the differential features of vibration reconstruction signals.
• Simulations and experimental validations are performed.

Main Results:

• The proposed phase unwrapping method effectively handles various optical feedback levels.
• The novel technique accurately determines both optical feedback factor (C) and linewidth enhancement ($ \alpha $) simultaneously.
• The study demonstrates the influence of $ \alpha $ accuracy on C evaluation.
• Experimental results confirm the efficacy of the proposed methods.

Conclusions:

• The developed phase unwrapping technique enhances the robustness of laser diode SMI.
• The simultaneous evaluation of optical feedback and linewidth enhancement improves sensing accuracy.
• This work offers a more reliable approach for vibration reconstruction and noncontact sensing in industrial settings.