Influences of laser source on phase-sensitivity optical time-domain reflectometer-based distributed intrusion sensor

Area of Science:

• Optoelectronics
• Fiber optic sensing
• Signal processing

Background:

• Distributed intrusion sensing relies on phase-sensitivity optical time-domain reflectometer (φ-OTDR) technology.
• Laser source characteristics, particularly frequency drift, can introduce noise and affect sensor performance.

Purpose of the Study:

• To investigate the influence of laser source frequency drift and pulse width on φ-OTDR performance.
• To propose and utilize a metric for quantifying trace-to-trace fluctuations.

Main Methods:

• Numerical simulations were conducted to model the relationship between frequency drift rate, pulse width, and trace-to-trace fluctuations.
• A fluctuations ratio coefficient (FRC) was developed to quantify these fluctuations.
• Experimental validation was performed using a φ-OTDR prototype, simulating high frequency drift rates.

Main Results:

• Simulation results indicate that FRC increases with higher frequency drift rates and pulse widths.
• The FRC reaches a peak and plateaus at elevated frequency drift rates and pulse widths.
• Experimental results align with simulations at high drift rates, confirming the analysis.

Conclusions:

• Laser frequency drift is a critical factor influencing φ-OTDR performance and intrusion detection accuracy.
• The findings provide guidance for selecting appropriate laser sources for φ-OTDR systems.
• Optimizing laser source parameters can enhance the overall reliability and sensitivity of distributed intrusion sensors.