Measuring the feedback parameter of a semiconductor laser with external optical feedback

Area of Science:

• Optoelectronics
• Laser Physics
• Metrology

Background:

• The feedback parameter (C factor) is crucial for semiconductor lasers with external optical feedback.
• Current self-mixing interferometry (SMI) methods for measuring C are limited to values below 3.5.
• Accurate C factor measurement is essential for understanding and controlling laser behavior under feedback.

Purpose of the Study:

• To develop a novel method for measuring the C factor in semiconductor lasers.
• To extend the measurable range of the C factor beyond existing limitations.
• To verify the proposed method through simulations and experimental validation.

Main Methods:

• Analysis of the phase signal of SMI signals in the frequency domain.
• Development of a new measurement technique based on frequency-domain analysis.
• Validation using both computational simulations and experimental data.

Main Results:

• The proposed frequency-domain method successfully measures the C factor.
• The new method extends the measurable C factor range up to approximately 10.
• Simulations and experimental results confirm the method's accuracy and effectiveness.

Conclusions:

• A novel and effective frequency-domain method for measuring the semiconductor laser C factor has been presented.
• This technique significantly expands the range of measurable C factor values.
• The findings provide a valuable tool for characterizing semiconductor lasers with external optical feedback.