Bright quadripartite entanglement from competing χ(2) nonlinearities

In this Brief Report, we investigate the generation of bright quadripartite entanglement of continuous variables in an experimentally realizable system involving second-order harmonic generation with competing nondegenerate optical parametric downconversion. By using the well-known van Loock-Furusawa criterion for continuous variable correlations, we find that the genuine quadripartite entanglement can be generated in the system over a wide range of controllable parameters. Besides this, it is shown that the bipartite entanglement between any two field modes can be achievable. In addition, the dependence of the quantum correlations on the pump parameter is also discussed.