The Poisson distributions of the coupled with |n〉^b (n = 1, 2,…) in the qubus beam on path b, in Eq. (6), by the process of QND, when |γ| = 100 and ϕ = 0.05. m is the photon number and p(m) is the probability to detect the photon number m in the Poisson distribution of by using the PNR detector. In Eq. (5) with |γ| = 100 and ϕ = 0.05, the overlaps of Poisson distributions for different values of photon numbernare negligible; thus, reliable discrimination between |n〉^b (n = 1,2,…) on the path b is possible.