Field-validated high-sensitivity distributed mass sensing using a triple-taper-based Φ-OTDR sensor

Area of Science:

• Fiber optic sensing
• Distributed sensing technology
• Optical metrology

Background:

• Traditional sensors struggle with sensitivity and accuracy in distributed mass detection.
• Phase-sensitive optical time-domain reflectometry (Φ-OTDR) offers potential but requires enhanced performance.
• Mechanical interaction between light and fiber is key to improving sensor sensitivity.

Purpose of the Study:

• To develop and validate a novel triple-tapered fiber structure for Φ-OTDR.
• To significantly enhance the sensitivity and accuracy of loading mass detection.
• To demonstrate the sensor's reliability in realistic field conditions.

Main Methods:

• Fabrication of a 5m sensing region with three sequential 20µm diameter tapers.
• Utilizing Φ-OTDR to analyze light-mechanical interactions within the tapered fiber.
• Experimental validation involving controlled mass loading and field deployment with simulated loads.

Main Results:

• Achieved a maximum signal-to-noise ratio (SNR) of 27.16 dB, a 30% improvement over non-tapered sensors.
• Demonstrated high mass sensitivity (0.601±0.017µs/g) and precise phase shift detection (0.168±0.009rad).
• Field validation showed strong correlation with laboratory benchmarks (RMSE=0.826, MAPE=1.92%), confirming accuracy and stability.

Conclusions:

• The triple-tapered fiber structure significantly enhances Φ-OTDR sensitivity for loading mass detection.
• The sensor provides accurate, reliable, and stable measurements in both laboratory and field settings.
• This technology holds promise for advanced distributed sensing applications requiring high precision.