Sensitivity of an optical feedback interferometer for acoustic waves measurements

Area of Science:

• Acoustics and Optics
• Metrology and Measurement Science

Background:

• Optical interferometers are sensitive tools for measuring physical quantities.
• Acoustic pressure measurement is crucial in various scientific and engineering fields.
• Understanding the sensitivity of optical feedback interferometers is key for their application in acoustics.

Purpose of the Study:

• To investigate and quantify the sensitivity of an optical feedback interferometer for measuring acoustic pressure from plane waves.
• To determine the factors influencing the sensitivity of the interferometer.
• To validate the interferometer's performance experimentally.

Main Methods:

• Linearizing the governing equations of the optical feedback interferometer to establish its sensitivity.
• Analyzing the dependence of sensitivity on configuration parameters like optical feedback and laser length.
• Conducting experimental validation using acoustic waveguides across a 0.5-18 kHz frequency range.

Main Results:

• The interferometer's sensitivity is independent of the acoustic wave frequency.
• Sensitivity is dependent on optical feedback parameters and the length of the laser path.
• Experimental results show a low mean relative error compared to a reference condenser microphone.

Conclusions:

• The optical feedback interferometer is a viable tool for broadband acoustic pressure measurement.
• The study provides a clear understanding of the sensitivity factors for this measurement technique.
• The method offers accurate acoustic pressure sensing with potential for wide-ranging applications.