Zhang Wei, Chen Weimin, Lei Xiaohua, Wang Chuhong
Appl Opt. 2017 Nov 20;56(33):9212-9220. doi: 10.1364/AO.56.009212.
Fiber Bragg grating (FBG) sensors are prone to spectral distortions in practical applications, which may cause large demodulation errors. There are many algorithms demodulating FBG spectra, but no approach is able to evaluate demodulation results under spectral distortions. To address this problem, four spectral indices are comparatively utilized to quantify distortions of spectra. Seven representative demodulation algorithms are adopted to analyze impacts of various simulated distorted spectra. Simulation results show that the side-mode suppression ratio (SMSR) of the spectrum is the most suitable spectral index for accuracy evaluation of demodulation results. In particular, when SMSR is larger than 6.3 dB, demodulation results will be accurate, and they are inaccurate when SMSR is smaller than 2.1 dB. The effectiveness of the proposed evaluation approach is validated with fatigue experiments of 9 FBG sensors.
光纤布拉格光栅（FBG）传感器在实际应用中容易出现光谱畸变，这可能会导致较大的解调误差。有许多算法用于解调FBG光谱，但没有一种方法能够在光谱畸变情况下评估解调结果。为了解决这个问题，比较使用了四个光谱指标来量化光谱畸变。采用七种代表性的解调算法来分析各种模拟畸变光谱的影响。仿真结果表明，光谱的边模抑制比（SMSR）是评估解调结果准确性的最合适光谱指标。特别是，当SMSR大于6.3 dB时，解调结果将是准确的，而当SMSR小于2.1 dB时，解调结果不准确。通过对9个FBG传感器的疲劳实验验证了所提出评估方法的有效性。
