Optimized Phase-Generated Carrier Demodulation Algorithm for Membrane-Free Fabry-Pérot Acoustic Sensor with High...

Area of Science:

• Optoelectronics
• Acoustic Sensing
• Signal Processing

Background:

• Demodulating fiber optic Fabry-Pérot (F-P) acoustic sensors with high sensitivity and dynamic range is challenging.
• Existing methods struggle with high sound pressure levels and maintaining signal integrity.
• Membrane-free F-P acoustic sensors require advanced demodulation techniques for optimal performance.

Purpose of the Study:

• To propose and validate an advanced phase-generated carrier (PGC) demodulation algorithm for membrane-free F-P acoustic sensors.
• To improve sensitivity, signal-to-noise ratio, and dynamic range, especially under high sound pressure.
• To achieve superior demodulation performance compared to traditional PGC algorithms.

Main Methods:

• An innovative PGC demodulation algorithm was developed, optimizing mixing phase delay.
• The cosine component of the filtered interference signal was introduced into the demodulation process.
• Experimental validation was performed under high sound pressure conditions, testing sensitivity, THD, minimum detectable sound pressure, and frequency response.

Main Results:

• The ameliorated algorithm achieved a demodulation sensitivity of 34.95 μrad/Pa and THD of 0.87%.
• A minimum detectable sound pressure of 129.73 mPa/Hz1/2 was obtained.
• The sensor demonstrated a wide dynamic range of 102.6 dB and a flat frequency response (±0.82 dB from 100 Hz to 33 kHz).

Conclusions:

• The proposed advanced PGC demodulation algorithm significantly enhances the performance of membrane-free F-P acoustic sensors.
• The algorithm is effective for high-sound-pressure measurements, offering superior sensitivity and dynamic range.
• This technology shows strong potential for applications in aerospace acoustic measurements.