Large-scale multiplexing of a FBG array with randomly varied characteristic parameters for distributed sensing

Area of Science:

• Photonics and Optical Sensing
• Fiber Optic Sensors
• Nanotechnology

Background:

• Fiber Bragg Gratings (FBGs) are crucial for optical sensing.
• Multiplexing FBGs is essential for large-scale sensing networks.
• Existing methods face challenges with crosstalk and limited capacity.

Purpose of the Study:

• To propose a novel method for large-scale multiplexing of FBG arrays.
• To address spectral-shadowing and multiple-reflection crosstalk.
• To enhance the capacity and accuracy of distributed fiber optic sensing systems.

Main Methods:

• Developing an FBG array with randomly varied characteristic parameters (RVCPs).
• Controlled random variation of center wavelengths and grating spacings.
• Utilizing low reflectivity FBGs (<-45 dB).

Main Results:

• Achieved large-scale multiplexing of 10,000 FBGs over a 10m fiber.
• Demonstrated significantly reduced spectral-shadowing and multiple-reflection crosstalk.
• Improved signal-to-noise ratio and demodulation accuracy in numerical and experimental tests.

Conclusions:

• The RVCP-FBG array enables unprecedented multiplexing capacity.
• This technology significantly enhances the performance of distributed fiber optic sensing.
• The proposed method offers a robust solution for scalable optical sensing applications.