Modified dual Mach-Zehnder interferometers with new locating algorithm for intrusion detection.

Area of Science:

• Optical Engineering
• Fiber Optic Sensing
• Interferometry

Background:

• Fiber-optic intrusion detection systems often suffer from polarization-induced fading.
• Existing dual Mach-Zehnder interferometer (DMZI) systems typically require polarization control loops.

Purpose of the Study:

• To present a new DMZI scheme that eliminates polarization-induced fading.
• To develop a novel algorithm for locating intrusion-induced disturbances.
• To demonstrate a robust and stable fiber-optic intrusion detection system.

Main Methods:

• Development of a novel dual Mach-Zehnder interferometer (DMZI) optical scheme.
• Implementation of a new algorithm for intrusion point localization.
• Experimental validation on a 250-meter fiber optic cable.

Main Results:

• The new DMZI scheme successfully eliminates polarization-induced fading without a polarization control loop.
• Intrusion location errors of less than 26 meters were achieved.
• The system demonstrated long-term operational stability with consistent performance over years.

Conclusions:

• The proposed DMZI system offers a robust solution for fiber-optic intrusion detection.
• The system provides accurate and reliable intrusion localization.
• The design ensures high interference visibility and stable locating capabilities over extended periods.