  We consider preparation of nonclassical oscillatory states in a degenerate
parametric oscillator combined with phase modulation. In this scheme
intracavity oscillatory mode is excited by train of Gaussian laser pulses
through degenerate down-conversion process and phase modulation element
inserted in a cavity leads to anharmonicity of oscillatory mode. We demonstrate
production of nonclassical oscillatory states with two-fold symmetry in
phase-space including the superposition of Fock states and quantum localized
states on the level of few excitation numbers and in over-transient dissipative
regime.
