Fiber-optic Bragg grating strain sensor with drift-compensated high-resolution interferometric wavelength-shift...

Area of Science:

• Optoelectronics and Photonics
• Materials Science and Engineering
• Mechanical Engineering

Background:

• Fiber Bragg gratings (FBGs) are widely used for sensing applications due to their unique spectral properties.
• Strain-induced wavelength shifts in FBGs are a primary method for strain measurement.
• Thermal variations can introduce significant drift, compromising the accuracy of FBG-based strain sensors.

Purpose of the Study:

• To describe a fiber Bragg grating strain sensor system utilizing interferometric wavelength shift determination.
• To incorporate a reference channel for compensating thermal-induced drift.
• To evaluate the system's capability in resolving sub-microstrain changes in quasi-static strain.

Main Methods:

• Employing interferometric techniques to precisely measure strain-induced wavelength shifts in FBGs.
• Integrating a reference channel within the system to actively compensate for temperature fluctuations.
• Applying quasi-static strain to the FBG sensor and analyzing the output signal.

Main Results:

• The developed system demonstrates the capability to resolve sub-microstrain changes.
• A resolution of approximately 6 x 10(-3) microstrain/radical Hz was achieved at a 1 Hz perturbation frequency.
• The reference channel effectively mitigated the impact of thermal drift on sensor output.

Conclusions:

• The described fiber Bragg grating strain sensor system offers high sensitivity and accuracy for quasi-static strain measurements.
• The integration of a reference channel significantly enhances the system's robustness against thermal drift.
• This technology holds promise for advanced structural health monitoring and precision metrology applications.