Continuous-variable entanglement assisted quantum communication through fiber channels

Based on the shared quantum entangled state, entanglement-assisted quantum communication presents advantages in increasing channel capacity. Up to now, most of the entanglement-based quantum communications with dense coding are limited to the proof-of-principle experiments. Toward practical application, it is essential to demonstrate entanglement-based quantum communication in fiber channel. Here, we experimentally demonstrate the deterministic entanglement-assisted quantum communication based on the continuous-variable entangled state through commercial fiber channels. By applying the encoding scheme of dense coding, we realize the simultaneously decoding of two non-commuting classical signals submerged in the shot noise of coherent beam with the help of the continuous-variable entangled beam after the transmission in a 10 km fiber channel. We show that the channel capacity of entanglement-assisted communication is higher than that of coherent state when weak classical signals are transmitted through fiber channels. We also experimentally demonstrate the one-sided device-independent random number generation through a 2 km fiber channel. In this experiment, we first distribute EPR steering through the fiber channel between two distant stations, then verify the existence of randomness at the local station, and finally extract quantum random numbers with a generation rate of 7.06 Mbits/s at the remote station, which is 2 km away from the entanglement source. The presented results makes a crucial step toward practical application of continuous-variable entanglement-assisted quantum communication.