Distributed fiber optics disturbance sensor using a dual-Sagnac interferometer.

Area of Science:

• Optoelectronics
• Fiber Optic Sensing
• Interferometry

Background:

• Distributed fiber optic sensing systems are crucial for monitoring infrastructure and detecting environmental changes.
• Traditional systems often suffer from coherent noise and polarization crosstalk, limiting performance.
• A robust and high-resolution sensing solution is needed to overcome these limitations.

Purpose of the Study:

• To demonstrate a novel distributed fiber optic disturbance sensing system.
• To reduce coherent noise and mitigate polarization crosstalk.
• To achieve high-frequency detection and precise spatial resolution.

Main Methods:

• Utilizing a dual-Sagnac interferometer configuration.
• Employing a single broadband light source operating at a consistent wavelength.
• Implementing a prototype system with a 1.3 Km fiber loop and a sampling rate of 32.8 kHz.

Main Results:

• The system effectively reduces coherent noise and avoids polarization crosstalk.
• The maximum detectable frequency reached the theoretical limit of 8.18 kHz.
• Achieved a spatial resolution of less than 15 meters within a frequency range of 50-4000 Hz.

Conclusions:

• The proposed dual-Sagnac interferometer-based fiber optic sensing system is effective.
• The system demonstrates significant improvements in noise reduction and crosstalk avoidance.
• The system offers high-frequency detection capabilities and excellent spatial resolution for disturbance sensing.