A Space-Division Multiplexing Method for Fading Noise Suppression in the Φ-OTDR System.

Area of Science:

• Optical Engineering
• Sensing Technology
• Signal Processing

Background:

• Phase-sensitive time-domain reflectometry (Φ-OTDR) enables distributed long-distance vibration monitoring.
• A significant challenge in Φ-OTDR is signal fading, leading to distorted phase extraction.

Purpose of the Study:

• To propose and evaluate a space-division multiplexing (SDM) based Φ-OTDR system for fading suppression.
• To introduce a frequency spectral similarity strategy for processing SDM signals.

Main Methods:

• Implementation of SDM using multi-core optical fiber (MCF).
• Development of a novel signal processing strategy based on frequency spectral similarity.
• Comparative analysis of the proposed method against existing strategies.

Main Results:

• Reduced distortion rate from an average of 9.34% to less than 2% over 270 seconds.
• Demonstrated the reliability of SDM for effective fading suppression in Φ-OTDR systems.
• Validated the improvement in fading suppression capability for commercial systems.

Conclusions:

• SDM is a viable technical approach to mitigate fading in Φ-OTDR.
• The frequency spectral similarity processing enhances the performance of SDM-based Φ-OTDR.
• This technique offers practical improvements for existing long-distance vibration monitoring systems.