The state evolution of a system of two-mode optical fields interacting
with a Kerr medium is investigated. It is discovered that at some spe
cial times the system evolves into a quantum superposition of a finite
number of different macroscopically distinguishable two-mode coherent
states, i.e., so-called two-mode Schrodinger-cat states. Especially t
he two-mode Yurke-Stoler state is achieved at half of the period of th
e system by taking proper parameters. The influence of detuning and di
ssipation on two-mode Schrodinger-cat states is also discussed.