从传感光纤的高双折射螺距和光纤结构两方面分析不同螺距下光纤内光的偏振态差异及其受温度变化的影响,对比了PANDA光纤、椭圆芯光纤、保偏微结构光纤的温度特性。结果表明,在全光纤电流传感器(FOCS)中,当传感光纤的螺距L_T是光纤对应的未螺旋状态下拍长L_p的2倍时,温度特性最差。L_T减小,光纤偏振保持能力减弱,抗物理干扰能力变差。当L_T≈L_p时,传感光纤既有较好的温度特性,也有较强的抗外界物理干扰能力。不同结构的传感光纤,传感器比差的范围不同,其中基于微结构保偏光纤的传感光纤,在-40~+70 ℃全温度下未经补偿,传感器比差变化范围最低,仅为±0.32%。

We analyze states of polarization in the fiber with different pitches and the influence of the environmental temperature on the fiber from the high-birefringence pitch and the structure of the sensing fiber. We compare the temperature characteristics of PANDA fiber, elliptical core fiber, and polarization-maintaining (PM) microstructure fiber, and make the conclusion that for a given fiber optic current sensor (FOCS), when the pitch of the sensing fiber LT is twice as long as the beat length Lp of the fiber in non-helical state, the temperature characteristic is the worst; when LT decreases, polarization-maintaining ability and anti-physical-interference ability weaken; when LT≈Lp, the sensing fiber has good temperature characteristics and strong anti-physical-interference ability. The sensing fibers with different structures have different ratio errors. Without compensation at the temperature of -40-+70 ℃, the sensing fiber based on PM microstructure fiber has a minimum value of ratio error ±0.32%.