Demodulation of a weak fiber Bragg grating array using a fiber delay line.

Area of Science:

• Optoelectronics
• Fiber optic sensing
• Acousto-optic devices

Background:

• Fiber Bragg gratings (FBGs) are widely used for sensing applications.
• Demodulating weak FBGs often requires complex setups.
• Interference-based techniques can enhance signal detection.

Purpose of the Study:

• To demonstrate a simple method for demodulating weak fiber Bragg grating (WBG) arrays.
• To utilize a fiber delay line (FDL) for WBG array signal extraction.
• To investigate the interference patterns generated by a WBG array with an FDL.

Main Methods:

• Constructing a fiber delay line (FDL) with a fiber-ring cavity.
• Matching the FDL's delay time to the interval of adjacent WBG sensors.
• Inducing interference between pulses reflected from different WBG elements.
• Analyzing the interference signals to demodulate the WBG array.

Main Results:

• Successfully demodulated a 5-WBG array using the FDL.
• Observed clear interference patterns resulting from the FDL.
• Demonstrated that the FDL enables signal emission based on interference.

Conclusions:

• A fiber delay line (FDL) provides a simple and effective method for demodulating weak fiber Bragg grating (WBG) arrays.
• The proposed FDL technique leverages optical interference for signal extraction.
• This approach offers a straightforward solution for WBG array sensing.