有缺口的磁环光学相干断层扫描的光学设计。The mathematics and physics model of OCT (Optical Current Transformer) with a gapped magnetic ring is briefly discussed in the paper. And some proposals of how to select the magnetic materials and crystals and reduce the stress birefringence of the crystal are also put forward in the paper. Based on the above, an OCT with 1000 A rated current is designed by using the ANSOFT Maxwell tools.