Wavelength dependence of the sensitivity of a bulk-glass optical current transformer

The wavelength dependence of the sensitivity of a bulk-glass optical current transformer is theoretically analyzed, simulated numerically and verified experimentally. The results show that the wavelength dependence will cause obvious sensitivity fluctuation of the system because of the existence of the dispersions of the reflection-induced retardance, Verdet constant, and the linear birefringence inside the bulk-glass current sensing head. Therefore, it is necessary to stabilize the driving current and the ambient temperature of the optical source of the sensor or compensate the harmful effects caused by wavelength variation. These results might be useful for researchers and designers working in the optical current transformer techniques area.