Electronic Noise in Optical Homodyne Tomography
  The effect of the detector electronic noise in an optical homodyne tomography experiment is shown to be equivalent to an optical loss if the detector is calibrated by measuring the quadrature noise of the vacuum state. An explicit relation between the electronic noise level and the equivalent optical efficiency is obtained and confirmed in an experiment with a narrowband squeezed vacuum source operating at an atomic rubidium wavelength. 
Juergen Appel, Dallas Hoffman, Eden Figueroa, A. I. Lvovsky