Theoretical Research On Magneto Optical Rotation Effect In Inhomogeneous Magnetic Field And Application To Optical Current Sensing Technology

In principle,the optical current transformer is universally recognized as the high-quality electronic current transformer due to its accurate measurement and natural insulativity.With more than half a century of world-wide joint efforts,the optical current transformer has experienced significant practical breakthrough.However,the measurement accuracy and operational reliability have not yet achieved the expected goals,and there is still far away from large scale application.To further promote the practical process of optical current transformer,it is necessary to continue to solve the related technical problems in combination with practice,and the theoretical problems embedded in the practical problems shall also be studied in depth.To further improve the measurement accuracy of optical current transformer as the application target,to discover and refine the scientific problems as the breakthrough point,the theoretical and technical research work of this report focuses on the non-equivalent nonreciprocal phenomenon of Faraday rotation effect.The main findings of this report are as follows.Firstly,the ‘equivalent nonreciprocal breaking phenomenon' of Faraday rotation effect was found.The equivalent nonreciprocal breaking phenomenon was discovered by accident in an experiment: in the nonuniform magnetic field spatial distribution environment,after switching back and forth the horizontal position of the straight-through type optical current sensing unit,the induction components of light output intensity are different.The conventional Faraday rotation effect theory could not explain this equivalent nonreciprocal ‘breaking' phenomenon.The authenticity of the ‘equivalent nonreciprocal breaking phenomenon' was confirmed by subsequent repeated experiments.It was shown that there is a non-equivalent nonreciprocal phenomenon in the Faraday rotation effect,the cause of which is the nonuniform distribution of the magnetic field.Secondly,the infinitesimal cascade Jones matrix model of non-uniformly induced medium was established.The magnetic field of nonuniform spatial distribution is a nonuniform physical field.The induction tensor produced by the nonuniform physical field is unevenly distributed along the optical path.The infinitesimal cascade Jones matrix model of non-uniformly induced medium was formed by the representation of non-uniformity by means of the ternary infinitesimal Jones matrix.The non-diagonal elements of the infinitesimal cascade Jones matrix model of non-uniformly induced medium are complex numbers with both real parts and imaginary parts as well as quaternary attributes.The non-equivalent nonreciprocal phenomenon of Faraday rotation effect is perfectly explained by the complex non-diagonal elements.Thirdly,the complete optical path model system of non-uniformly induced medium was presented.There is redundancy in the infinitesimal cascade Jones matrix.With eigen-analysis,the infinitesimal cascade Jones matrix is transformed into the ternary Jones matrix model of non-uniformly induced medium through the unitary transformation,with various basic physical parameters,namely medium induction angle,medium phase shift difference and medium nonuniform angle.Different from the previous binary Jones matrix,the ternary mode l presents a new physical parameter characterizing the nonuniform physical field effect: the medium nonuniform angle.Based on the ternary Jones matrix,an optical path model system of non-uniformly induced medium composing of medium tensor,Jones matrix,optical vector equation and light intensity formula is formed.Fourthly,the mechanism of the non-equivalent nonreciprocal phenomenon of Faraday rotation effect was revealed.The medium nonuniform angle is the reciprocal physical quantity,which is the key to the non-equivalent nonreciprocity of Faraday rotation effect.The reciprocal medium nonuniform angle produced by nonuniform magnetic field causes the non-equivalent nonreciprocity for medium tensor,Jones matrix,optical vector equation and induction component of light output intensity of non-uniformly induced magneto-optic medium,resulting in the ‘equivalent nonreciprocal breaking phenomenon'.The optical path perception of the non-equivalent nonreciprocal phenomenon of Faraday rotation effect is the equivalent magnetic field,that is,the weighted integral of the nonuniform magnetic field along the optical path.Finally,the equivalent nonreciprocal optical current sensing technique was formed.Characterized by the combination value of zero for forward/backward transmission of reciprocal physical quantities,the optical current induction technique with property of equivalent nonreciprocity is formed,with total reflection technique and mean of forward/backward transmission multiplexing of straight-through type optical current sensing unit.The equivalent nonreciprocal optical current transformer was developed.The experimental results showed that the developed optical current transformer can resist the influence of magnetic field non-uniformity on the measurement accuracy,and has the advantages of accurate measurement and reliable operation,which can meet the conditions of operation in network.