A Method for Suppressing Error of Fiber Optic Current Transformer Caused by Temperature Based on λ/4 Wave Plate Fabricated With Polarization-Maintaining Photonic Crystal Fiber

The beat length of
$\lambda $
/4 wave plate of fiber optic current transformer (FOCT) will change with the temperature fluctuation of environment, which will result in additional phase error, reducing the accuracy of current measurement. In this article, we presented an FOCT based on
$\lambda $
/4 wave plate fabricated with polarization-maintaining photonic crystal fiber (PCF). Combined with the error model caused by the
$\lambda $
/4 wave plate in FOCT, we analyzed the specific mechanism of temperature influence on the
$\lambda $
/4 wave plate. Aiming at the problem of fusing PCF to panda polarization-maintaining fiber, we optimized the related parameters of fiber fusion splicer to reduce the fusion loss of the fiber. It was experimentally verified that the beat length of PCF is less sensitive to temperature than that to elliptical-core polarization-maintaining fiber. Finally, we measured the current of FOCT utilizing two kinds of
$\lambda $
/4 wave plates in a full temperature range from −40 °C to 70 °C. It was verified that it is insensitive to temperature for FOCT when utilizing PCF
$\lambda $
/4 wave plate, with the corresponding system current measurement accuracy at 0.5S level.