Noise analysis of the fiber-based vibration detection system

Area of Science:

• Physics
• Geophysics
• Optical Engineering

Background:

• Fiber-based continuous wave (CW) laser interferometers are crucial for seismic event detection.
• Optimizing these systems requires a thorough understanding and analysis of their noise levels.
• Previous research has not fully quantified the relationship between system noise and detection performance.

Purpose of the Study:

• To analyze the noise characteristics of a fiber-based CW laser interferometer system for seismic detection.
• To determine the impact of varying fiber length and laser noise on detection sensitivity.
• To establish a quantitative relationship between background noise and seismic detection results.

Main Methods:

• Two vibration detection systems were established to analyze noise levels.
• Experiments involved varying fiber lengths (0-100 km) and laser noise levels.
• Key performance indicators including Power Spectral Density, Background Noise Level, and Signal-to-Noise Ratio were utilized.

Main Results:

• The system successfully detected minor phase changes caused by 160 µm fiber length vibrations.
• A clear relationship between the system's background noise and its detection results was established.
• Quantitative analysis provided insights into factors affecting system sensitivity.

Conclusions:

• This research provides a quantitative framework for understanding and optimizing fiber-based seismic detection systems.
• The findings serve as a valuable reference for designing more efficient vibration detection systems.
• Minimizing background noise is critical for enhancing the sensitivity and effectiveness of seismic event detection.