Abstract: The garnet with grooved films (Ta (50 nm)/Nd2Fe14B (500 nm)/Ta (50 nm),Ta (50 nm)/Nd2Fe14B (1 000 nm)/Ta (50 nm) grooved films) is the sensitive element of the optical current transformer.Degree of polarization (DOP) is the ratio of the light intensity of polarization section and the entire section of the light intensity.The rotating garnet controlled by MCU has no effect on degree of polarization of incident beam;however,rotating garnet with grooved films is capable of modulating the polarization of the laser beam.And DOP domain by this method is larger than that of light passing through disordered medium.The results provide a theoretical basis both for the measurement accuracy of the garnet-type photoelectric current transformer and structural improvements.

Key words: garnet;polarization modulation;MCU;optical current transformer