Novel Fiber Bragg Grating Sensing Method Based on the Sidelobe Modulation for Ultrasound Detection
Novel Fiber Bragg Grating Sensing Method Based on the Sidelobe Modulation for Ultrasound Detection
复制标题
基于旁瓣调制的新型光纤布拉格光栅超声检测传感方法
DOI：
10.1109/jlt.2018.2862635
复制
发表时间：
2019
影响因子：
4.7
通讯作者：
Wang Xin
中科院分区：
文献类型：
--
作者：
Lian Sheng;Tjin Swee Chuan;Lin Bo;Sheng Xinzhi;Lou Shuqin;Zhang Yongxin;Wang Xin
这一贡献展示了光纤布拉格光栅（FBG）和超声之间的相互作用。当光栅长度远大于超声波波长时，传统的波长调制方法失效。为了找到一种有效的检测方法，在这种情况下，一种新的旁瓣调制已被提出和研究。当光栅长度远大于超声波波长时，光栅的布拉格波长不发生偏移，而旁瓣的反射率受到超声波的周期性调制，这是一种有效的超声波传感方法。为了优化该方法的性能，进一步分析了不同超声位移幅值、频率和光栅长度下的旁瓣特性。分析结果表明，选择合适的光栅长度，可以使旁瓣调制在合适的超声频率和振幅范围内实现对超声的探测。实验结果表明，在波长调制无效的情况下，利用5 mm光纤光栅，通过简单的强度解调，我们提出的旁瓣调制方法可以有效地检测7.8 MHz的超声波。
This contribution demonstrates the interaction between the fiber Bragg grating (FBG) and the ultrasound. When the grating length is much longer than the ultrasonic wavelength, the conventional wavelength-modulation method is invalid. In order to find out an effective sensing method, in this case, a novel sidelobe modulation has been proposed and investigated. When grating length is much longer than the ultrasonic wavelength, the Bragg wavelength is not shifted; however, the reflectivity of sidelobe is modulated by ultrasound, periodically, which can be utilized as an effective ultrasound sensing method. In order to optimize the performances of this method, the characteristics of the sidelobes are further analyzed for different ultrasonic displacement amplitude, frequency, and grating length, respectively. The analysis results indicate that a proper choice of the grating length would enable the sidelobe modulation to be utilized for detecting the ultrasound with an appropriate range of ultrasonic frequency and amplitude. This method is preliminarily validated in the experiment, and the experimental results show that our proposed sidelobe-modulation method is effective to detect the 7.8 MHz ultrasonic wave by a simple intensity-demodulation using a 5 mm FBG, where the wavelength modulation is invalid.