反射式光纤电流传感的锁相检测法与近似误差

Signal detection and approximate error of reflecting fiber-optic current sensing

对反射式Sagnac型全光纤电流传感器中光信号的检测方法进行了深入的分析,并对固有的小角近似误差进行了充分的理论分析和数值模拟。针对反射式光纤电流传感器中极其特殊的信号检测要求,采用了锁相检测法来处理传感信号。商用化的光纤电流传感器的误差一般要求小于0.2%,而在各类检测方法的信号处理中,一个必须的步骤是sinθ≈θ,该步骤造成的小角近似误差极大地影响了整个系统的测量精度。通过对这2个问题进行深入的分析与模拟,对解决光纤电流传感器的检测方法设计、测量精度、灵敏度等问题提供了较大的参考价值。

The optical signal detection of fiber-optic current transducer （ FOCT）, based on the in-line Sagnac interferometer,is analyzed in detail. The theoretical analysis and digital simulation of approximate error are also developed sufficiently. The phase-locked detection method used in the special system is described. The error of commercial FOCT should be less than 0.2 % , sin θ≈θ, which is usefull and necessary for signal processing. It is one of the bad factors that lower the measurement precision. The detailed analysis and simulation of the two subjects are valuable for solving a great deal of problems, such as signal detection, measurement precision, measurement sensitivity,et al.