Photon number uncertainty of states out of cascaded Mach-Zehnder interferometer with DOPAs

We have studied a cascaded nonlinear interferometer having degenerate optic al parametric amplifiers, one for each arm. The nonlinear interferometer ge nerates supposed squeezed state. The photon statistics of tile states of th e output ports of tile interferometer are analyzed in tcr ms of the photon number uncertainty and the power of the mean, as a function of the gain of the crystals and the amplified input source intensity. If the nonlinear cas caded interferometer is used, it is possible to reduce the photon number un certainty enormously.