Time-division multiplexing of large serial fiber-optic Bragg grating sensor arrays

Area of Science:

• Photonics and Optical Sensing
• Fiber Optic Sensors
• Multiplexing Techniques

Background:

• Fiber-optic Bragg grating (FBG) sensors are crucial for measuring strain and temperature.
• Time-division multiplexing (TDM) offers a promising approach for interrogating FBG sensor arrays.
• Optimizing TDM systems for high sensitivity and low cross-talk is essential for practical applications.

Purpose of the Study:

• To investigate the performance parameters of TDM-based FBG sensor systems.
• To identify methods for enhancing sensitivity and minimizing cross-talk in FBG sensor interrogation.
• To propose and experimentally validate a novel demultiplexing technique for improved FBG sensing.

Main Methods:

• Examining the performance of TDM systems for FBG sensor arrays.
• Implementing a short time resolution in the demultiplexing process.
• Utilizing an electro-optic modulator for high-resolution (400-ps) signal gating in demultiplexing.

Main Results:

• Demonstrated a novel demultiplexing method using an electro-optic modulator.
• Achieved a strain resolution of 0.15 microepsilon/sqrt(Hz) within a 50-Hz bandwidth.
• Verified the system's capability to handle at least 50 time-addressed sensors on a single fiber.
• Showcased significant performance improvements through short time resolution demultiplexing.

Conclusions:

• Short time resolution in demultiplexing greatly improves TDM FBG sensor system performance.
• The proposed electro-optic modulator-based method enables high-sensitivity, low-cross-talk FBG sensing.
• The demonstrated system is scalable and suitable for interrogating multiple sensors on a single fiber.