The method for acoustic pressure calibration based on fiber Bragg grating

All-fiber photoacoustic sensing, characterized by its compact size and ease of integration, has significant potential in applications such as non-destructive testing and structural health monitoring. Traditional calibration of photoacoustic transducers relies on high-frequency hydrophones, which are limited to liquid environments, posing challenges for realtime calibration in air. This study introduces a novel method for photoacoustic pressure calibration based on fiber Bragg gratings (FBGs), which are well-known for their high sensitivity and wavelength division multiplexing capabilities. We establish a theoretical model linking photoacoustic pressure, FBG reflection spectra, and photodetector responsivity. By constructing an FBG-based photoacoustic pressure calibration system, we validate its performance against a standard highfrequency hydrophone (PA FOHS, England), achieving a calibration error of just 0.6%. Unlike conventional hydrophonebased methods, this approach allows for calibration in non-liquid environments, expanding its applicability. We anticipate that this method will advance the use of all-fiber photoacoustic technology in various fields, including non-destructive testing and structural health monitoring.