Wu Qi, Okabe Yoji
Appl Opt. 2015 Feb 1;54(4):694-8. doi: 10.1364/AO.54.000694.
Fiber Bragg grating (FBG) demodulated by an erbium fiber laser (EFL) has been used for ultrasonic detection recently. However, due to the inherent relaxation oscillation (RO) of the EFL, the detected ultrasonic signals have large deformations, especially in the low-frequency range. We proposed a novel data processing method to reconstruct an actual ultrasonic waveform. The noise spectrum was smoothed first; the actual ultrasonic spectrum was then obtained by deconvolution in order to mitigate the influence of the RO of the EFL. We proved by experiment that this waveform reconstruction method has high precision, and demonstrated that the FBG sensor demodulated by the EFL will have large practical applications in nondestructive testing.
最近，由掺铒光纤激光器（EFL）解调的光纤布拉格光栅（FBG）已被用于超声检测。然而，由于EFL固有的弛豫振荡（RO），检测到的超声信号有很大的变形，尤其是在低频范围内。我们提出了一种新颖的数据处理方法来重建实际的超声波形。首先对噪声频谱进行平滑处理；然后通过去卷积获得实际的超声频谱，以减轻EFL的RO的影响。我们通过实验证明了这种波形重建方法具有很高的精度，并表明由EFL解调的FBG传感器在无损检测中将有很大的实际应用。
