Clusters on the basis of bright multimode light in a mixed state

The possibility of cluster-state generation on the basis of mixing radiation from two independent lasers in an asymmetric Mach–Zehnder interferometer is shown in this paper. The formulation of the problem is close to that considered before by Menicucci (Phys. Rev. A 83, 62314 (2011)) and Yokouama et al. (Nature Photonics 7, 982 (2013)). The specificity of the current consideration is that our sources of squeezed light (phase-locked sub-Poissonian lasers) radiate bright light in a mixed state, in contrast to an optical parametric oscillator in the subthreshold mode. We also take into account the multimode structure of the radiation, not restricting ourselves to only a constant component of the field-noise characteristics. To set the cluster state, the van Loock–Furusawa separability criterion is used.