Optimization of High-Order Quarter-Wave Plate for Residual Birefringence Suppression in FOCS

Abstract

Fiber optic current sensors (FOCS) are widely adopted in modern power grids due to high sensitivity, excellent insulation, and strong immunity to electromagnetic interference. This prominence necessitates precise investigation into their error sources and corresponding optimization. This study examines reflective FOCS based on the Faraday effect. A theoretical model is established to simulate phase error caused by linear birefringence from the quarter-wave plate. Conventional methods using circular birefringence are analyzed, revealing inherent limitations. Innovatively, a compensation strategy employing high-order quarter-wave plates is proposed to effectively eliminate linear birefringence effects. This approach significantly enhances the accuracy and practicality of FOCS in precision metrology.