Compact FPI-Based Fiber Optic Humidity Sensors Functionalized with PMMA/PVA/PEG.

Area of Science:

• Optoelectronics
• Fiber Optics
• Chemical Sensing

Background:

• Fiber optic sensors offer advantages in harsh environments.
• Fabry-Pérot interferometers (FPI) are suitable for sensing applications.
• Developing compact and sensitive humidity sensors is crucial.

Purpose of the Study:

• To design and fabricate novel FPI-based fiber optic humidity sensors.
• To investigate the humidity sensing performance of different polymer coatings.
• To evaluate the potential of these sensors for practical applications.

Main Methods:

• Heterogeneous splicing of single-mode fiber to hollow-core fiber for FPI fabrication.
• Dip-coating and withdrawal technique to apply polymethyl methacrylate (PMMA), polyvinyl alcohol (PVA), and polyethylene glycol (PEG) films.
• Experimental characterization of sensor response to humidity variations.

Main Results:

• Three distinct FPI-based fiber optic humidity sensors were successfully fabricated.
• PEG-functionalized FPI sensors showed the highest sensitivity to humidity, approximately ten times greater than PMMA-coated sensors.
• PMMA-coated FPI sensors exhibited the lowest humidity sensitivity.

Conclusions:

• The developed FPI-based fiber optic humidity sensors offer a compact and robust sensing solution.
• The PEG-functionalized sensor demonstrates significant potential for high-sensitivity humidity detection.
• These sensors are suitable for integration into spatially restricted or electrically hostile environments.