Intensity-demodulated fiber-ring laser sensor system for acoustic emission detection

Area of Science:

• Photonics
• Sensing Technology
• Materials Science

Background:

• Fiber-optic sensors offer advantages in harsh environments.
• Fiber Bragg gratings (FBGs) are widely used for sensing applications.
• Ultrasonic detection is crucial for non-destructive testing and structural health monitoring.

Purpose of the Study:

• To develop and demonstrate a cost-effective fiber-optic ultrasonic sensor system.
• To utilize a fiber-ring laser incorporating an FBG for ultrasonic detection.
• To explore the potential of this system for acoustic emission monitoring.

Main Methods:

• Theoretical modeling and experimental validation of a fiber-ring laser sensor.
• Integration of a regular fiber Bragg grating (FBG) as the sensing element.
• Employment of a tunable optical band-pass filter (TOBPF) to set the lasing wavelength on the FBG's spectral slope.
• Detection of ultrasonic signals via laser output intensity variations caused by FBG spectral shifts and cold-cavity loss modulations.

Main Results:

• Successful demonstration of a fiber-optic ultrasonic sensor system.
• The system leverages ultrasonically-induced FBG spectral shifts to modulate laser intensity.
• The sensor exhibits a simple structure and low cost.

Conclusions:

• The proposed fiber-optic ultrasonic sensor system is effective for detecting ultrasonic signals.
• Its simple design and low cost make it a promising candidate for acoustic emission detection in structure health monitoring.
• This technology offers a viable solution for real-time structural integrity assessment.