Study on the Intrinsic Temperature Compensation of the Polarization Rotation Detection for Industrial Manufacturing of Fiber-Optic Current Sensor

For fiber-optic current sensors located in highvoltage substations require a measurement uncertainty of less than 0.2% over a wide temperature range from −45° C to 85° C for power monitoring. To reach a low interference between the optical sensor and the ambient temperature, the concept of polarization rotation detection of polarimetric In-Line fiberoptic current sensors has been previously presented. In advance, this study presents how fiber-coils can be intrinsically compensated by the utilization of polarization rotation detection, by de-adjusting the rotation angle of the quarter-wave retarder. This shifts the temperature dependency of the bias quarter-wave retarder along a cosine-function and introduces an additional perturbation, which counteracts the contribution of the Verdet-constant from SiO2. The presented temperature compensation is far less complex than the current state of art temperature compensation by fiber-retarder detuning, as precise rotation adjustments can be automatically manufactured during the active alignment process of optical sub-assemblies.