给出了反射式Sagnac型光纤电流互感器(RS-FOCT)检测相位差与传感光纤Verdet常数及线性双折射、1/4波片相位延迟、相位调制器尾纤偏振串音和延迟光纤偏振串音等参数的定量关系,确定了它们的温度相关性是造成户外型RS-FOCT变比误差的主要原因,并采用传感光纤螺旋绕制、变比误差自补偿、降低相位调制器和延迟光纤偏振耦合等方法加以抑制.分析了RS-FOCT偏振非互易误差的产生机理,提出了偏振器尾纤快轴通光消除非互易波列相干性的误差抑制方法.实验结果表明:在-40～60℃范围内,敏感环路温度变化时变比误差不超过±0.2％;相位调制器、延迟光纤温度变化造成的变比变化量分别由1.828％和5.96％减小到0.283％和0.053 1％;偏振器输入尾纤温度变化引起的互感器输出准周期振荡被抑制.%The phase difference detected by a reflective Sagnac interferometer-type fiber optic current transformer (RS-FOCT as a function of the Verdet constant and linear birefringence of the sensing fiber,phase retardation of quarter-wave retarder,pigtail polarization crosstalk of integrated optical phase modulator and polarization crosstalk of the polarization-maintaining delay fiber are given respectively.The temperature dependences of these parameters are determined to be major causes of the scale factor error of the RS-FOCT applied to the outdoor environment.Some error suppression measures are taken to improve the temperature performance of the RS-FOCT including winding the sensing fiber spirally,the self-compensation of the scale factor temperature error and lowering the polarization coupling intensity of the phase modulator and delay fiber.The polarization nonreciprocal error mechanism of the RS-FOCT is analyzed with the corresponding error suppression method.The method aligns the fast axis of the pigtail and integrated optical waveguide of the polarizer so that the coherence between the nonreciprocal waves can be eliminated.Over the temperature range from-40 ℃ to 60 ℃,the scale factor error caused by the sensing loop is within 0.2 ％,and the scale factor changes caused by the temperature variation of the phase modulator and delay fiber are reduced from 1.828％ to 0.283％ and from 5.96％ to 0.053 1％ respectively,in addition,the quasi-periodic oscillation of the RS-FOCT output with the temperature of the input pigtail of the polarizer is greatly suppressed.
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