基于双超辐射发光二极管(SLED)光源研究了空间电扫描型低相干干涉长距离光纤传感解调系统。通过负透镜扩束搭建了紧凑解调干涉光路,分析了双SLED光源功率比对低相干干涉条纹形态的影响并探讨了传输损耗的功率比补偿。针对双SLED光源干涉条纹的特点,提出了双阈值的任意极值解调算法,并进行了压力解调实验。结果表明,在50~180 k Pa的压力范围内,利用不同峰值,可以实现0.24%~0.40%F.S.(F.S.为全量程)的解调精度,光纤传输距离达到1.76 km,与理论分析吻合。 Based on double superluminescent light-emitting diode (SLED) light source, space-power scanning low-coherence interference long-distance optical fiber sensing demodulation system is studied. The compact demodulation interference optical path was constructed by negative lens expander. The influence of the power ratio of double SLED source on the interference morphology of low coherence interference fringes was analyzed and the power ratio compensation of transmission loss was discussed. According to the characteristics of interference fringes of double SLED light source, an arbitrary extreme value demodulation algorithm with double threshold is proposed and the pressure demodulation experiment is carried out. The results show that the demodulation accuracy of 0.24% ~ 0.40% F.S. (F.S. Is the full scale) can be achieved by using different peaks in the pressure range of 50 ~ 180 kPa, and the optical fiber transmission distance reaches 1.76 km, which is in good agreement with the theoretical analysis.