利用光纤超荧光光源在1530 nm附近具有较好的线性边带做边沿滤波器进行滤波解调,并对边沿滤波和光源的工作原理进行了深入分析。由于光源波长检测灵敏度对系统解调灵敏度起决定作用,所以系统光源采用了双程后向结构,在线性边带的下降沿2.5 nm范围内功率随波长变化的灵敏度为-14.7 μW/nm,线性拟合度达到了0.9995。系统采用全光结构,提高了解调速度。通过对地震检波的模拟测量,解调检测波长灵敏度可达-1.27 pm/mV,应变分辨力为1.06 με。实验表明,该解调系统具有操作简单、灵敏度高、稳定性好、性价比高且反应速度快,可以实现对地震信号的实时检测。

The filtering demodulation is realized by using the good linear sideband near 1530 nm of the super-fluorescent fiber source.The light source of system adopts double-pass backward configuration,because the detecting sensitivity of light source decides the whole system′s sensitivity.When the linear sideband is 2.5 nm,the sensitivity of power is -14.7 μW/nm,and the degree of fitting is 0.9995.The system uses all-optical structure to improve the demodulation speed.By the way of computer simulation,its detection sensitivity for the wavelength and strain separately are -1.27 pm/mV and 1.06 με.The results show that this demodulation system has high sensitivity,good stability,quick demodulation speed,and it can realize real-time detection of seismic wave.