System optimization of a long-range Brillouin-loss-based distributed fiber sensor.

Area of Science:

• Optics and Photonics
• Materials Science
• Sensor Technology

Background:

• Distributed fiber sensors offer long-range monitoring capabilities.
• Brillouin-loss-based systems are susceptible to spectral distortion and measurement errors.
• Optimizing system parameters is crucial for improving sensor performance.

Purpose of the Study:

• To develop a high-performance 25 km Brillouin-loss-based distributed fiber sensor.
• To investigate and mitigate factors causing spectrum distortion and measurement errors.
• To achieve superior spatial resolution and strain accuracy over an extended range.

Main Methods:

• Investigated Brillouin spectrum distortion and measurement errors related to probe pulse amplification.
• Determined optimal pulse pairs using differential Brillouin gain evolution analysis.
• Employed differential pulse-width pair Brillouin optical time domain analysis.
• Utilized dispersion-shifted fiber to accommodate high-power probe pulses.

Main Results:

• Identified low continuous-wave pump power as essential for reducing measurement error.
• Achieved a 25 km sensing range.
• Realized a spatial resolution of 30 cm.
• Obtained a strain accuracy of ±20 με.

Conclusions:

• The optimized Brillouin-loss-based distributed fiber sensor demonstrates state-of-the-art performance for its length.
• System parameter optimization, particularly pump power and pulse pair selection, is critical for high-fidelity measurements.
• The developed sensor technology has significant potential for long-range structural health monitoring and other applications.