In 3-mode Fock space we find a new tripartite entangled state |α,γ〉λ, which make up a new quantumparametric down-conversion amplifier. Application of the state is briefly discussed.
A new kind of tripartite coherent-entangled state (CES) ∣β,γ,x⟩μντ is proposed, which exhibits the properties of both coherence and entanglement. We investigate its completeness and orthogonality, and find it can make up a representation of tripartite CES. A protocol for generating the tripartite CES is proposed using asymmetric beam splitter. Applications of the tripartite CES in quantum optics are also presented.