利用保偏延迟光纤环的偏振耦合模型，考虑幅值较大的互易性寄生波列，计算了光纤电流互感器(FOCS)光路系统的干涉光强，得到了互感器变比与延迟环偏振串音之间的理论关系，揭示了延迟环偏振串音的温度相关性对互感器变比的影响机理，并提出了抑制方法。为保证变温环境下互感器的变比误差在0.2%以内，延迟环的偏振串音应低于-30 dB。实验结果表明：在绕制延迟环的过程中，降低绕环张力、减少胶的用量，采用低温度系数骨架可有效地改善互感器变比的温度稳定性，在-40 ℃～70 ℃范围内，互感器变比的变化量由0.63%降低至0.07%。该研究为光纤电流互感器中保偏延迟光纤环的设计和绕制工艺提供了理论指导。

According to the polarization coupling model of the polarization-maintaining delay optical fiber coil, considering the reciprocal parasitic waves with large amplitude, the interference intensity of the optical system in the fiber-optic current sensor (FOCS) is calculated, and the theoretical relationship between the scale factor and the polarization crosstalk of the delay fiber coil is obtained. The effect mechanism of the temperature dependence of the polarization crosstalk on the scale factor is revealed, and the corresponding suppression methods are proposed. To ensure the scale factor error to be within 0.2% under the varied temperature condition, it is essential for the polarization crosstalk of the delay fiber coil to be less than -30 dB. The experimental results show that the temperature performance of the FOCS can be improved greatly when lowering the tension of winding fiber, reducing the quantity of the glue, and utilizing the frame with low temperature coefficient. The variation of the scale factor is decreased from 0.63% to 0.07% over the temperature range from -40 ℃ to 70 ℃. The research work offers a theoretical guide for the design and manufacture of the optical fiber delayed coil in the FOCS.