We analyze the properties of nonclassical number states, specifically
squeezed number states D(alpha)S(z)\n], and find their maximum signal-
to-quantum noise ratio. It is shown that the optimal signal-to-quantum
noise ratio for these states decreases as 1/(2n + 1)(2), where n is t
he photon number, from the optimal value as derived by Yuen [Phys, Let
t. A 56 (1976) 105], (C) 1998 Elsevier Science B.V. All rights reserve
d.