Highly sensitive curvature fiber sensor based on an enhanced core diameter mismatch

Area of Science:

• Optoelectronics
• Fiber Optics
• Sensor Technology

Background:

• Curvature sensing is crucial in various engineering applications.
• Existing fiber optic sensors often face limitations in sensitivity or structural complexity.
• High-order cladding modes offer potential for enhanced sensing performance.

Purpose of the Study:

• To experimentally propose and theoretically investigate a novel fiber optic curvature sensor.
• To enhance curvature sensitivity by utilizing an enhanced core diameter mismatch.
• To evaluate the sensor's performance, including sensitivity, temperature, and strain responses.

Main Methods:

• Fabrication of the sensor by splicing step multimode and coreless fibers.
• Excitation of high-order cladding modes for improved curvature sensing.
• Experimental measurement of curvature sensitivity at different wavelengths.
• Testing of temperature and strain cross-sensitivity.

Main Results:

• Achieved high curvature sensitivities of -114.74 nm/m^-1 (1272 nm), -91.08 nm/m^-1 (1408 nm), and -61.10 nm/m^-1 (1644 nm).
• Demonstrated minimal influence from temperature and strain on curvature measurements.
• The sensor operates effectively within a measuring range of 0-0.49778 m^-1.

Conclusions:

• The proposed fiber optic sensor offers a simple structure, easy fabrication, and high mechanical strength.
• The enhanced core diameter mismatch effectively improves curvature sensitivity.
• This sensor has potential applications in material mechanics and advanced optical fiber sensor design.