Lyu Chengang, Wu Chuang, Tam Hwa-Yaw, Lu Chao, Ma Jianguo
School of Electronic Information Engineering,Tianjin University,Tianjin 300072, China.
Opt Express. 2013 Jul 29;21(15):18273-80. doi: 10.1364/OE.21.018273.
A DBR fiber grating laser acoustic sensor based on polarization beat signal modulation analysis has been demonstrated for directional acoustic signal measurement. The acoustic sensor was fabricated in birefringent erbium-doped fiber, and the influences of external-acoustic pressure on fiber grating laser sensor were analyzed, considering the effect of relative orientation of the acoustic wave on the degrees of birefringence modulation. In experiment, the birefringence in sensing fiber was modulated by ultrasonic pressure. Agreement between theoretical and experimental results was obtained for ultrasound wave propagating from different directions (0-360 degrees in 15 degrees intervals) corresponding to a nonlinearly change in beat frequency modulation rates. The results demonstrate that the DBR fiber grating laser acoustic sensor has an orientation recognizable ability, offering a potential for acoustic vector signal detection.
一种基于偏振拍信号调制分析的分布式布拉格反射（DBR）光纤光栅激光声学传感器已被用于定向声学信号测量。该声学传感器是在双折射掺铒光纤中制造的，考虑了声波相对取向对双折射调制程度的影响，分析了外部声压对光纤光栅激光传感器的影响。在实验中，传感光纤中的双折射由超声压力调制。对于从不同方向（以15度间隔从0到360度）传播的超声波，对应于拍频调制率的非线性变化，理论结果与实验结果取得了一致。结果表明，DBR光纤光栅激光声学传感器具有方向识别能力，为声学矢量信号检测提供了潜力。
