There　are　some　significant　defects　in　the　existing　optical　current　transducers　(OCTs),　such　as　optical　power　dependence,　non-linear　demodulation　with　Malus　law,　linear　birefringence,　etc.　These　defects　severely　hurt　the　reliability,　stability,　and　accuracy　of　OCTs　in　long-term　applications.　The　main　idea　to　become　free　of　these　defects　is　to　have　a　linear　sense　of　the　Faraday　rotation　angle.　To　this　end,　the　paper　presents　a　linear　OCT　based　on　a　strip　aluminum　polarization　grating,　which　directly　converts　the　Faraday　rotation　angle　into　a　synchronous　line　movement　of　a　light　spot.　It　then　positions　the　spot　to　measure　the　current.　It　has　no　optical　power　dependence,　realizes　a　linear　sense　of　the　Faraday　rotation　angle,　reduces　the　effect　of　temperature　drift,　almost　eliminates　linear　birefringence,　improves　long-term　stability,　and　achieves　a　0.2S　class　accuracy.　©　2001-2012　IEEE.