  Based on the correspondence between Collins diffraction formula (optical
Fresnel transform) and the transformation matrix element of a three-parameters
two-mode squeezing operator in the entangled state representation (Opt. Lett.
31 (2006) 2622) we further explore the relationship between output field
intensity determined by the Collins formula and the input field's probability
distribution along an infinitely thin phase space strip both in spacial domain
and frequency domain. The entangled Wigner function is introduced for
recapitulating the result.
