Temperature Compensation in Fiber Optic Current Sensor Based on Inherent Polarization Quality Factor

We propose and demonstrate a temperature compensation method based on the inherent polarization quality factor (PQF) of the quarter-waveplate in the fiber optic current sensors. The PQF, dependent on the temperature, can act as a temperature sensor with a resolution of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2~^{\circ }$ </tex-math></inline-formula>C in the experiment. The new compensation coefficient based on PQF is derived from the both relationships of the PQF and the temperature-dependent ratio error. This method can achieve the temperature compensation through internal PQF value instead of direct temperature, and need not require an external temperature sensor to monitor ambient temperature. The new compensation can achieve the accuracy of ratio error 0.2% within the temperature range of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$- 40~^{\circ }$ </tex-math></inline-formula>C to <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$+ 72~^{\circ }$ </tex-math></inline-formula>C, which is satisfied with the 0.2 Class accuracy.