PLC-AWG-based FBG demodulation system for high-frequency vibration measurement

Area of Science:

• Photonics and Optical Engineering
• Sensor Technology
• Integrated Optics

Background:

• Fiber Bragg Gratings (FBGs) are crucial for sensing applications.
• Existing FBG demodulation systems face limitations in speed and accuracy.
• Arrayed Waveguide Gratings (AWGs) offer potential for high-performance optical signal processing.

Purpose of the Study:

• To propose and demonstrate a novel FBG demodulation system utilizing AWGs.
• To design, fabricate, and integrate key components for the system.
• To evaluate the system's performance in terms of accuracy, speed, and acceleration error.

Main Methods:

• Designed and fabricated an AWG chip on a silica-on-silicon planar lightwave circuit (PLC) platform.
• Integrated the AWG with a photodiode (PD) array and developed demodulation circuitry including TIAs and ADCs.
• Implemented high-speed data acquisition and transmission via an Ethernet interface.

Main Results:

• Achieved a wavelength demodulation accuracy of 4.24 pm.
• Demonstrated a demodulation rate exceeding 200 kHz.
• Obtained an average demodulation acceleration error better than 22.8 mg.

Conclusions:

• The proposed AWG-based FBG demodulation system offers high accuracy and speed.
• The compact system is suitable for high-frequency vibration sensing applications.
• This technology advances optical sensing capabilities for demanding environments.