Long-distance distributed pressure sensing based on frequency-scanned phase-sensitive optical time-domain...

Area of Science:

• Fiber optics
• Optical sensing technologies
• Distributed sensing systems

Background:

• Traditional distributed sensing systems face limitations in range and spatial resolution.
• Developing specialized optical fibers is crucial for enhancing sensor performance.
• Phase-sensitive optical time-domain reflectometry ( Ф-OTDR) offers potential for high-sensitivity measurements.

Purpose of the Study:

• To propose and demonstrate a long-distance distributed pressure sensing system.
• To investigate a novel fiber with enhanced pressure sensitivity and low loss.
• To achieve high spatial resolution and accurate pressure discrimination.

Main Methods:

• Utilizing a specially designed fiber with two large air holes in the cladding.
• Employing frequency-scanned phase-sensitive optical time-domain reflectometry ( Ф-OTDR).
• Analyzing the distinct pressure responses of orthogonal polarization axes.

Main Results:

• Demonstrated distributed pressure sensing over a 720 m range with 5 cm spatial resolution.
• Achieved 14,400 resolved sensing points with a pressure uncertainty of 0.49 bar.
• Successfully discriminated between pressure and temperature/strain responses using polarization characteristics.

Conclusions:

• The proposed system offers a robust solution for long-distance distributed pressure sensing.
• The specialized fiber design significantly enhances pressure sensitivity and reduces signal loss.
• Further optimization of fiber parameters can potentially improve temperature sensitivity for advanced applications.