  A quantum communication network can be constructed by distributing a
multipartite entangled state to space-separated nodes. Entangled optical beams
with highest flying speed and measurable brightness can be used as carriers to
convey information in quantum communication networks. Losses and noises
existing in real communication channels will reduce or even totally destroy
entanglement. The phenomenon of disentanglement will result in the complete
failure of quantum communication. Here, we present the experimental
demonstrations on the disentanglement and the entanglement revival of
tripartite entangled optical beams used in a quantum network. We discover that
symmetric tripartite entangled optical beams are robust in pure lossy but
noiseless channels. While in a noisy channel the excess noise will lead to the
disentanglement and the destroyed entanglement can be revived by the use of a
correlated noisy channel (non-Markovian environment). The presented results
provide useful technical references for establishing quantum networks.
