A Fading Suppression Method for Φ-OTDR Systems Based on Multi-Domain Multiplexing

Area of Science:

• Optoelectronics
• Fiber Optic Sensing
• Signal Processing

Background:

• Phase-sensitive optical time domain reflectometry (Φ-OTDR) is widely used but suffers from fading noise, leading to false alarms and limiting applications.
• Existing single-domain multiplexing methods like spatial-domain multiplexing (SDM), polarization-domain multiplexing (PDM), and frequency-domain multiplexing (FDM) have limitations in comprehensive fading noise suppression.

Purpose of the Study:

• To propose and experimentally validate a novel fading suppression method for Φ-OTDR systems based on multi-domain multiplexing (MDM).
• To analyze the principles and limitations of existing single-domain multiplexing techniques.
• To determine optimal parameter combinations for MDM to achieve effective fading noise suppression.

Main Methods:

• Analysis of single-domain multiplexing (SDM, PDM, FDM) principles and limitations.
• Detailed explanation of the multi-domain multiplexing (MDM) principle.
• Experimental setup to evaluate MDM with various parameter combinations (FDM frequencies, SDM intervals, PDM).

Main Results:

• Single-domain multiplexing methods alone are insufficient for comprehensive fading noise suppression.
• Optimized parameter combinations of MDM, including FDM frequencies, SDM intervals, and PDM, effectively suppress fading noise.
• MDM provides an optimal balance between performance and hardware complexity, achieving fade-free measurements.

Conclusions:

• Multi-domain multiplexing (MDM) is a superior strategy for combating fading noise in Φ-OTDR systems compared to single-domain methods.
• Optimized MDM offers a robust and practical solution for achieving reliable, fade-free measurements.
• This work presents a promising technical advancement for the widespread engineering application of Φ-OTDR technology.