Aiming to the idea of that “the Faraday effect will be doubled and the linear birefringence will be eliminated by using a return-back optical path”,the equivalent matrices of Orthoconjugate Reflection (OCR)-typed,Direct Reflection (DR)-typed,and Roof-prism Reflection (RPR)-typed optical current sensor models are derived,respectively. The results show that the OCR-typed return-back optical path can eliminate the effects of the linear birefringence,while the DR-typed and the RPR-typed return-back optical paths can not do that when the Faraday rotation is zero;all of these three return-back optical paths can not eliminate the effects of the linear birefringence when the Faraday rotation is not zero. Therefore,it is worthy to discuss that whether the view of “the Faraday effect will be doubled and the linear birefringence will be eliminated by using a return-back optical path” is correct for the bulk glass optical current sensór employing the conventional“-/+”signal processing scheme.