High-sensitivity strain sensor based on a Fabry-Pérot interferometer with a tapered capillary structure

Area of Science:

• Optoelectronics
• Fiber Optics Sensing
• Materials Science

Background:

• Accurate strain measurement is crucial for structural health monitoring.
• Existing sensors often face challenges with sensitivity and temperature cross-sensitivity.
• Fabry-Pérot interferometers (FPI) offer potential for high-performance sensing applications.

Purpose of the Study:

• To propose and demonstrate a high-sensitivity strain sensor.
• To minimize temperature cross-sensitivity for precision measurements.
• To develop a cost-effective fabrication method for FPI sensors.

Main Methods:

• Fabrication of an FPI sensor by fusing a tapered capillary glass tube between two single-mode fibers.
• Experimental characterization of strain response in the range of 0 to 202.84 με.
• Measurement of temperature sensitivity and strain-temperature cross-sensitivity between 30 °C and 80 °C.

Main Results:

• Achieved a high strain sensitivity of 32.19 pm/με.
• Demonstrated low temperature sensitivity of 3.26 pm/°C.
• Recorded minimal strain-temperature cross-sensitivity of 0.101 με/°C.
• Exhibited excellent sensor stability and repeatability.

Conclusions:

• The proposed tapered capillary FPI sensor offers superior strain sensitivity and low temperature cross-sensitivity.
• The cost-effective fabrication method makes it suitable for practical implementation.
• The sensor shows significant potential for structural health monitoring in aerospace, civil infrastructure, and energy systems.