Continuous−variable quantum key distribution (CV−QKD) technology has emerged as a pivotal direction in quantum secure communication due to its inherent compatibility with classical optical communication systems and high key rates within metropolitan areas. However, the secret key rates of existing CV−QKD systems remain insufficient to meet the practical requirements of one−time pad encryption within metropolitan areas. This work innovatively integrates orthogonal frequency−division multiplexing (OFDM) technology into CV−QKD systems. We experimentally demonstrated, for the first time, a multi−carrier CV−QKD system operating at a 10 GHz repetition rate. Moreover, this experimental system respectively achieves secret key rates of 1819.32, 1078.48, 374.19, 112.96, and 34.63 Mbps over transmission distances of 5, 10, 25, 50, and 75 km by developing a high−precision dual−stage phase noise compensation algorithm, establishing an excess noise theoretical model, and designing a high−throughput data post−processing scheme. Notably, our work realizes the first instance of Gbps−level secret key rates within 10 km and 100 Mbps−level secret key rates within 50 km for metropolitan−area CV−QKD. Compared to traditional single−carrier CV−QKD system with 10 GHz repetition rate under identical experimental conditions, the multi−carrier key rate gains at different transmission distances can respectively reach 1.09@5 km, 1.10@10 km, 1.13@25 km, 1.54@50 km, and 5.55@75 km. These results confirm that the multi−carrier CV−QKD system scheme can significantly enhance quantum key distribution performance, providing an effective solution for future broadband and long−distance quantum secure communication.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |