Parallel generation of 31 tripartite entangled states based on optical frequency combs

Quantum entangled states, especially those having particular properties, are key resources for quantum information and quantum computation. In this paper, we put forward a new scheme to produce 31 continuous-variable (CV) tripartite entanglement fields based on three optical frequency combs via cascade nonlinear processes in an optical parametric cavity, and investigate the spectral characteristics of three frequency combs. The center wavelengths of the three combs are designed as 852 nm, 780 nm (atomic transition lines), and 1550 nm (fiber communication wavelength). The positivity under partial transposition (PPT) criterion, which is sufficient and necessary, is used to evaluate the entanglement in each group of comb lines. This scheme is experimentally feasible and valuable for constructing quantum information networks in future.