Entanglement and Self-Pulsing Instability
  We study the Wigner function of phase-locked nondegenerate optical parametric oscillator and find the signatures of both phase-locking and self-pulsing phenomena in phase space. We also analyze the problem of continuous-variable entanglement in the self-pulsing instability regime. 
N. H. Adamyan, S. B. Manvelyan, and G. Yu. Kryuchkyan