Optical Fiber Sensor with Dynamically Responsive Cladding for Real-Time Breath Pattern Monitoring

Area of Science:

• Materials Science
• Biomedical Engineering
• Sensor Technology

Background:

• Real-time humidity monitoring is crucial for health, industry, and agriculture.
• Optical fiber sensors offer potential for breath humidity analysis in clinical settings.

Purpose of the Study:

• To develop and demonstrate a novel optical fiber-based humidity sensor.
• To enable real-time monitoring of exhaled breath humidity for respiratory pattern analysis.

Main Methods:

• Fabrication of an optical fiber sensor with a biopolymer cladding (n=1.52) on a PMMA core (n=1.49).
• Characterization of sensor response to humidity changes, focusing on refractive index modulation and total internal reflection (TIR).
• Integration into a miniaturized platform for proof-of-concept breath monitoring.

Main Results:

• The sensor demonstrated real-time humidity monitoring with a sensitivity of 0.18 dB/%RH (40-70% RH) and 9.4 dB attenuation reduction at 70% RH.
• The device successfully detected and differentiated nasal and oral breathing patterns with a 1.3 s time resolution.
• No saturation was observed under high humidity conditions, indicating robustness.

Conclusions:

• The developed optical fiber sensor shows significant potential for long-term breath humidity monitoring.
• This technology can aid in early detection of abnormal breath patterns and advance next-generation healthcare.
• The biopolymer cladding's dynamic response to humidity enhances TIR for improved sensor performance.