Quadrature entanglement and photon-number correlations accompanied by   phase-locking
  We investigate quantum properties of phase-locked light beams generated in a nondegenerate optical parametric oscillator (NOPO) with an intracavity waveplate. This investigation continuous our previous analysis presented in Phys.Rev.A 69, 05814 (2004), and involves problems of continuous-variable quadrature entanglement in the spectral domain, photon-number correlations as well as the signatures of phase-locking in the Wigner function. We study the role of phase-localizing processes on the quantum correlation effects. The peculiarities of phase-locked NOPO in the self-pulsing instability operational regime are also cleared up. The results are obtained in both the P-representation as a quantum-mechanical calculation in the framework of stochastic equations of motion, and also by using numerical simulation based on the method of quantum state diffusion. 
H.H. Adamyan, N.H. Adamyan, S.B. Manvelyan, G.Yu. Kryuchkyan