Quantum communication based on two-mode entangled state with quantum noise locking method.

The two-mode entangled state is an important basic non-classical state and it has been used in many quantum communication projects. We propose a new quantum communication scheme with a two-mode entangled state which can transmit signals encoded by a thermal-state light field. Also, instead of locking several phases in the whole process, we use only one locking servo system at the final stage. The locking error signal comes from the measured quantum variances by using the quantum noise locking method. A proof-of-principle derivation shows that it is very convenient to achieve the secure condition against individual attacks. It would be utilized in practical quantum information process.