Research on continuous variable quantum cryptography with unbalanced basis choice

With its security based on quantum no-cloning and Heisenberg uncertainty relation, the quantum cryptography is a newly developed key distribution protocol. The recent research on continuous variable quantum cryptography assumes that the choice of basis is balanced. However, the performance of continuous variable quantum cryptography is an interesting but open question. By introducing the asymmetry in the shared bipartite two-mode entanglement state, the secret key rate was improved with unbalanced basis. Furthermore, numerical simulations with typical continuous variable quantum key distribution experiment show that the secure distance can be prolonged by 20km for a given secure key rate.