A Passive Ladder-Shaped FBG Sensor Network with Fault Detection Using Time- and Wavelength-Division Multiplexing

Area of Science:

• Optical Engineering
• Sensor Technology
• Photonics

Background:

• Fiber Bragg Grating (FBG) sensors are crucial for various monitoring applications.
• Multiplexing multiple FBGs in a single fiber enhances system efficiency.
• Distinguishing signals from multiplexed sensors, especially in complex topologies, remains a challenge.

Purpose of the Study:

• To develop and evaluate a method for simultaneous interrogation of multiplexed FBG sensors.
• To improve the signal-to-noise ratio for weak reflected signals.
• To assess the fault detection capabilities of the proposed sensor interrogation system.

Main Methods:

• Implementation of a ladder topology for multiplexing fiber Bragg grating sensors.
• Utilizing time- and wavelength-division multiplexing for simultaneous interrogation.
• Employing heterodyne detection to enhance the signal-to-noise ratio of reflected signals.
• Simulation of failure cases to evaluate fault detection.

Main Results:

• Successful simultaneous interrogation of seven FBGs was demonstrated.
• The heterodyne detection technique significantly improved the signal-to-noise ratio.
• The fault detection capability of the system was evaluated through simulations.

Conclusions:

• The proposed method enables efficient and reliable interrogation of multiplexed FBG sensors.
• The system shows promise for robust monitoring applications requiring fault tolerance.
• Further research can explore scalability and real-world deployment of this technique.