Long-period fiber gratings with variable coupling for real-time sensing applications

Area of Science:

• Fiber optic sensing
• Photonics
• Materials science

Background:

• Traditional fiber-grating sensors often rely on wavelength shifts.
• Real-time, high-sensitivity strain and temperature monitoring is crucial in various applications.

Purpose of the Study:

• To demonstrate a long-period grating sensor with fixed wavelength resonance.
• To achieve high-resolution strain and temperature measurements using a simplified sensor design.

Main Methods:

• Fabrication of a long-period grating.
• Experimental setup to measure resonance strength variations with temperature and strain.
• Characterization of sensor performance.

Main Results:

• The developed long-period grating exhibited resonance strength modulation, while the wavelength remained constant under varying temperature and strain.
• The sensor successfully resolved strain changes as small as 1 microstrain (µε).
• Temperature changes of 0.04 degrees Celsius (°C) were detectable.

Conclusions:

• This novel fiber-grating sensor offers a robust and simplified approach for real-time strain and temperature monitoring.
• The fixed-wavelength resonance design eliminates the need for spectrometers, reducing system complexity and cost.
• The demonstrated high sensitivity makes it suitable for precise measurement applications.