  Quantum dense coding (QDC) means to transmit two classical bits by only
transferring one quantum bit, which has enabled high-capacity information
transmission and strengthened system security. Continuousvariable QDC offers a
promising solution to increase communication rates while achieving seamless
integration with classical communication systems. Here, we propose and
experimentally demonstrate a high-speed quantum radio-frequency-over-light
(RFoL) communication scheme based on QDC with entangled state, and achieve a
practical rate of 20 Mbps through digital modulation and RFoL communication.
This scheme bridges the gap between quantum technology and real-world
communication systems, which bring QDC closer to practical applications and
offer prospects for further enhancement of metropolitan communication networks.
