  Multi-color entangled states of light including low-loss optical fiber
transmission and atomic resonance frequencies are essential resources for
future quantum information network. We present the experimental achievement on
the three-color entanglement generation at 852 nm, 1550 nm and 1440 nm
wavelengths for optical continuous variables. The entanglement generation
system consists of two cascaded non-degenerated optical parametric oscillators
(NOPOs). The flexible selectivity of nonlinear crystals in the two NOPOs and
the tunable property of NOPO provide large freedom for the frequency selection
of three entangled optical beams, so the present system is possible to be
developed as practical devices used for quantum information networks with
atomic storage units and long fiber transmission lines.
