High-sensitivity strain sensor based on inflated long period fiber grating.

Area of Science:

• Fiber Optic Sensors
• Photonics
• Materials Science

Background:

• Long Period Fiber Gratings (LPFGs) are widely used in sensing applications.
• Photonic Crystal Fibers (PCFs) offer unique light manipulation properties.
• Enhancing sensor sensitivity and stability remains a key research objective.

Purpose of the Study:

• To demonstrate a high-sensitivity strain sensor based on an inflated LPFG (I-LPFG).
• To investigate the fabrication of I-LPFGs using a novel pressure-assisted CO(2) laser technique.
• To evaluate the strain and temperature sensing performance of the fabricated I-LPFG.

Main Methods:

• Inscribing I-LPFGs by periodically inflating air holes of a PCF using a pressure-assisted CO(2) laser beam scanning technique.
• Characterizing the strain response of the I-LPFG.
• Performing high-temperature annealing and evaluating the sensor's repeatability and stability for temperature response.

Main Results:

• Achieved a high strain sensitivity of -5.62 pm/µε for the I-LPFG sensor.
• Demonstrated good repeatability and stability of temperature response after high-temperature annealing.
• Reported a temperature sensitivity of 11.92 pm/°C.

Conclusions:

• The developed I-LPFG sensor exhibits significantly enhanced strain sensitivity.
• The pressure-assisted CO(2) laser inscription technique is effective for fabricating high-performance fiber gratings.
• The I-LPFG sensor shows potential for reliable strain and temperature monitoring applications.