Robust and high-efficiency demodulation of ultra-weak FBG arrays in OFDR-based distributed sensing

Area of Science:

• Optical Engineering
• Photonics
• Sensing Technology

Background:

• Optical Frequency Domain Reflectometry (OFDR) is crucial for sensing applications.
• Ultra-weak Fiber Bragg Gratings (UWFBG) offer sensitive detection but face demodulation challenges.
• Existing Fiber Bragg Grating (FBG) inscription imperfections cause spectral distortion, hindering traditional demodulation.

Purpose of the Study:

• To propose and demonstrate a robust and high-efficiency demodulation scheme for OFDR-based UWFBG systems.
• To overcome limitations in FBG inscription technology affecting demodulation accuracy and efficiency.
• To enhance the practical applicability of OFDR-based UWFBG sensing.

Main Methods:

• The study proposes a novel demodulation scheme based on the Buneman Frequency Estimation (BFE) algorithm.
• The BFE algorithm is adapted for demodulating rough cross-correlation spectra of FBGs.
• This approach combines the noise resistance of cross-correlation with the efficiency of BFE.

Main Results:

• The proposed algorithm achieves robust demodulation performance, comparable to traditional methods.
• Demodulation efficiency is significantly enhanced by 15.3 times over a 10-m measurement range.
• The method effectively addresses spectral splitting and distortion issues caused by FBG inscription imperfections.

Conclusions:

• The developed demodulation scheme offers a substantial improvement in efficiency and robustness for OFDR-based UWFBG sensing.
• This advancement paves the way for more reliable and widespread practical applications of UWFBG sensor technology.
• The algorithm successfully mitigates the impact of FBG inscription imperfections on sensing data.