在实际测量过程中由于各种条件的限制，如非理想的5050分束器、本底光与信号光的干涉效率和探测器有限的共模抑制比，都将造成实际测量的结果不能如实反映压缩态的水平。基于平衡零拍探测(BHD)的理论背景，结合干涉效率对压缩度的影响，定量分析了非理想平衡零拍探测系统对测量压缩度的影响，构建了压缩度测量偏差、实际压缩度、5050分束器的分束比、本底光与信号光的干涉效率和平衡零拍探测器的共模抑制比(CMRR)的关系。该分析结果对于量化压缩度的测量误差、估算压缩光产生系统的实际压缩度有重要意义。

Due to the limitation of various conditions in the actual measurement, such as non-ideal 5050 beam splitter, balanced homodyne detector and interference efficiency, which are adverse to characterizing the squeezed state by the balanced homodyne detection (BHD) system. On the basis of the theoretical background of the BHD, the influence of the non-ideal BHD including the splitter ratio of 5050 beam splitter, the common mode rejection ratio (CMRR) of BHD and the interference efficiency on the measured squeezing degree are analyzed quantitatively, and the function of the deviation value is built with the real squeezing degree, splitter ratio of 5050 beam splitter, interference efficiency and CMRR. The result is very important for quantify the measuring error, and infer the real squeezing degree from the measured squeezing degree.