While the transmission rate is still too low to handle images, the researchers at Shanghai Jiao Tong University said the 300km (186 miles) optical fibre network was theoretically scalable, showing the viability of this kind of quantum network.
According to the paper, published in the May issue of the peer-reviewed Science Bulletin, the quantum secure direct communication (QSDC) network uses multiple lasers or pumps to send paired photons between users, with added noise to help hide the signals.
“The transmission distance or the number of users acts as a constraint on the construction of long-distance, large-scale quantum communication networks,” the researchers said in the paper.
“The realisation of a 10,000km-level quantum communication network containing hundreds or thousands of users represents a significant challenge that requires urgent attention,” they added.
There are three main forms of communication that take advantage of quantum physics phenomena to securely send data using particles – typically photons – along optical fibre cables.
