对于同一量子压缩光场，采用正交振幅噪声和强度差噪声测量方案会得到不同的压缩度，对此进行了理论解释。在输出信号无损耗的情况下，强度差噪声和正交振幅噪声的压缩度都随着增益的增大而增大，但前者小于后者。考虑损耗时，强度差噪声的压缩度反而大于正交振幅噪声的压缩度，说明正交化的振幅噪声压缩度对损耗更加敏感。

For the same quantum squeezed field, the squeezing degree is different for the measurement schemes of amplitude-quadrature noise and intensity-difference noise, which is theoretically explained. When the output signal has no loss, the squeezing degrees of intensity-difference noise and amplitude-quadrature noise increase with the increase of gain, but the degree of the former is smaller than that of the latter. When the loss is considered, the squeezing degree of intensity-difference noise is larger than that of amplitude-quadrature noise, which indicates that the squeezing degree of amplitude-quadrature noise is more sensitive to loss.