Temperature-insensitive directional transverse load sensor based on dual side-hole fiber Bragg grating

Area of Science:

• Optoelectronics
• Fiber Optics Sensing
• Materials Science

Background:

• Fiber Bragg gratings (FBGs) are widely used for sensing applications.
• Traditional FBG sensors often suffer from cross-sensitivity to transverse load and temperature.
• Dual side-hole fiber (DSHF) offers unique birefringence properties that can be exploited for specialized sensing.

Purpose of the Study:

• To propose and demonstrate a temperature-insensitive directional transverse load sensor.
• To investigate the directional load sensing capabilities of an FBG inscribed in DSHF.
• To evaluate the sensor's performance and suitability for intelligent monitoring.

Main Methods:

• Inscribing a fiber Bragg grating (FBG) into a section of dual side-hole fiber (DSHF).
• Applying directional transverse loads at 15° increments and monitoring wavelength shifts.
• Conducting finite element analysis (FEA) to simulate strain distribution.
• Testing the sensor's response to temperature variations.

Main Results:

• The DSHF-FBG sensor exhibited directional transverse load sensitivity with maxima and minima.
• Maximum load sensitivity of 699 pm/(N/mm) along the slow axis and minimum of 285 pm/(N/mm) along the fast axis.
• Achieved a low temperature sensitivity of 1.5 × 10⁻² pm/°C, demonstrating temperature insensitivity.

Conclusions:

• The developed DSHF-FBG sensor effectively measures directional transverse loads with high sensitivity.
• The sensor's minimal temperature sensitivity makes it robust for real-world applications.
• Its compact size and performance characteristics are suitable for intelligent transverse load monitoring systems.