Extrinsic Fabry-Perot interferometric optical fiber hydrogen detection system.

Area of Science:

• Materials Science
• Optical Engineering
• Chemical Sensing

Background:

• Hydrogen gas detection is critical for industrial safety.
• Existing sensors may have limitations in sensitivity or operational range.
• Optical fiber sensors offer potential for remote and robust hydrogen monitoring.

Purpose of the Study:

• To develop a new optical fiber hydrogen sensor system.
• To utilize a palladium silver (Pd-Ag) coated extrinsic Fabry-Perot interferometer (EFPI).
• To enable monitoring of hydrogen concentrations below the lower explosive limit.

Main Methods:

• Coating an EFPI with a palladium silver (Pd-Ag) film.
• Utilizing the mechanical stress induced by hydrogen absorption in the Pd-Ag film as the sensing mechanism.
• Employing a modified cross-correlation method for absolute air gap length determination.
• Implementing a temperature compensation method using an optical switch.

Main Results:

• Demonstrated a functional optical fiber hydrogen sensor system.
• Compared the performance of Pd-Ag films with different thicknesses.
• Successfully compensated for temperature variations affecting sensor readings.
• Validated the sensor's suitability for detecting low hydrogen concentrations.

Conclusions:

• The developed Pd-Ag coated EFPI sensor is effective for hydrogen detection.
• The sensor system provides accurate measurements below the lower explosive limit.
• The integrated temperature compensation enhances reliability for practical applications.