Long-range and wide-band vibration sensing by using phase-sensitive OFDR to interrogate a weak reflector array

Area of Science:

• Photonics and Optical Sensing
• Fiber Optic Technology
• Distributed Sensing Systems

Background:

• Traditional vibration sensing methods often face limitations in range and frequency response.
• Distributed fiber-optic sensing offers potential for long-distance monitoring but requires advanced techniques for waveform analysis.
• Phase-sensitive optical frequency domain reflectometry (ϕ-OFDR) is an emerging technology for high-resolution optical measurements.

Purpose of the Study:

• To propose and demonstrate a novel quasi-distributed fiber-optic vibration sensing system.
• To achieve wide-frequency vibration measurement over extended distances.
• To validate the system's performance through experimental testing.

Main Methods:

• The system utilizes a single-mode fiber (SMF) with strategically placed auxiliary weak reflection points.
• Phase-sensitive optical frequency domain reflectometry (ϕ-OFDR) is employed for signal detection and analysis.
• Vibration data is acquired by detecting changes at these auxiliary reflection points.

Main Results:

• The proposed system successfully measured single-point and multi-point vibrations.
• A wide-frequency response was achieved for vibration measurements.
• Experimental validation confirmed successful sensing capabilities over a 100 km fiber optic link.

Conclusions:

• The developed quasi-distributed fiber-optic vibration sensing system demonstrates effective long-range measurement capabilities.
• This research represents the first reported instance of wide-band vibration waveform measurement over 100 km using a reflectometry-based system.
• The findings highlight the potential of ϕ-OFDR for advanced distributed sensing applications.