Entangled light in transition through the generation threshold
Gagik Yu. Kryuchkyan, L. A. Manukyan · Physical Review A · 2004
We investigate continuous-variable entangling resources on the basis of two-mode squeezing for all operational regimes of a nondegenerate optical parametric oscillator with allowance for quantum noise of an arbitrary level. The results for the quadrature variances of a pair of generated modes are obtained by using the exact steady-state solution of the Fokker-Planck equation for the complex-$P$-representation quasiprobability distribution function. We find a simple expression for the squeezed variances in the near-threshold range and conclude that the maximal two-mode squeezing reaches 50% relative to the level of vacuum fluctuations and is achieved at the pump field intensity close to the generation threshold. The distinction between the degrees of two-mode squeezing for monostable and bistable operational regimes is cleared up.