干涉型光纤传感器的分集消偏振衰落技术的信号处理

Signal Processing with Divide/Combine Depolarization-Induced- Fading Technique of an Interferometric Fiber-Optic Sensor

对干涉型光纤传感器的分集检测消偏振衰落技术进行了理论分析,提出了将各路信号平方后相加的信号处理方式,使之能实现单元及阵列的实时消偏振衰落信号检测。通过理论计算,可以使干涉信号幅度波动小于4.7dB,并得出三路检偏是分集检测的最简取值的结论,通过信号处理电路,能够在信噪比略有降低的情况下消除偏振衰落的影响,实现干涉型光纤传感器的消偏振衰落,并设计了用于阵列的分集检测的实现方式。

A theoretical analysis is carried out for the divide/combine depolarization-induced-fading technique of an interferometric fiber-optic sensor. A processing method that adds the squared signals from various channels and thus can achieve real-time signal detection of unit and array by means of depolarization-induced-fading technique is proposed. The theoretical calculation shows the maximum fluctuation amplitude of the interferometric signal can be less than 4.7dB and a conclusion that three-channel polarization is the simplest value of divide/combine detection is obtained. Through signal processing circuit, the effect of polarization-induced-fading technique can be eliminated and the depolarization-induced-fading of an interferometric fiber-optic sensor can be achieved with a few SNR dropping. The scheme of divide/combine detection used for array is designed.