The quantum research team at China Telecom Corporation Limited (China Telecom) has successfully integrated quantum key distribution (QKD) signals with classical optical signals in a single fiber achieving transmission distance over 80 kilometers, at speeds of 10 Tb/s or higher.
This breakthrough, published in the Journal of Lightwave Technology, significantly conserves fiber resource savings and reduces the deployment costs of QKD networks. Traditionally, reducing the impact of strong classical signals on QKD typically involve reducing classical optical power, which inherently conflicts with standard optical communication network specifications and impedes the widespread adoption of QKD networks.
In this project, the research team explored the feasibility of integrating QKD networks with high-capacity classical optical networks without significant modifications to the existing infrastructure and validated wavelength allocation strategies for their co-existence in field-deployed shared fibers. Notably, the team demonstrated the co-propagation of QKD with high-power classical signals (with a total launch power of 21.75 dBm) over 81 km of commercial backbone fiber, covering 90 percent of China Telecom’s inter-site links.
(Executive editor: Yuan Ting)
