Kawakami Tetsuo, Kawahara Hiroki, Okamura Toshihiko, Maeda Wakako
Advanced Network Research Laboratories, NEC Corporation, Kawasaki 211-8666, Kanagawa, Japan.
Entropy (Basel). 2025 Jan 8;27(1):45. doi: 10.3390/e27010045.
We demonstrated the coexistence of an S-band CV-QKD signal with fully loaded C+L-band classical signals for the first time. The secret key rate of the S-band QKD system was 986 kbps with the C+L-band WDM signals transmitted through a 20 km G.654.E fiber link. We also revealed that the S-band CV-QKD performance limiting factor under the C+L-band WDM condition is the spontaneous Raman scattering light similar to the C-band CV-QKD performance limiting factor, confirming the validity of estimating the wavelength dependency of the secret key rate under the WDM condition from the fiber loss and the spontaneous Raman scattering light power. These results show that the CV-QKD performance under the C+L band WDM conditions becomes comparable to that under the C-band WDM conditions by wavelength design in the S-band.
我们首次证明了S波段连续变量量子密钥分发（CV-QKD）信号与满载的C+L波段经典信号共存。通过20公里的G.654.E光纤链路传输C+L波段波分复用（WDM）信号时，S波段QKD系统的密钥率为986 kbps。我们还发现，在C+L波段WDM条件下，S波段CV-QKD性能的限制因素是自发拉曼散射光，这与C波段CV-QKD性能的限制因素类似，证实了根据光纤损耗和自发拉曼散射光功率来估计WDM条件下密钥率的波长依赖性的有效性。这些结果表明，通过在S波段进行波长设计，C+L波段WDM条件下的CV-QKD性能变得与C波段WDM条件下的性能相当。
