Simultaneous quantum and classical communication using continuous variable
Bing Qi · arXiv (Cornell University) · 2016
Conventionally, classical optical communication systems employing strong laser pulses and quantum key distribution (QKD) systems working at single-photon levels are quite different communication modalities. Dedicated devices are commonly required to implement QKD. Here we show these two can be implemented simultaneously using the same information carriers. More specially, we propose a coherent communication scheme where both the binary bits for a classical communication protocol and Gaussian distributed random numbers for a QKD protocol are encoded on the same weak coherent pulses, and decoded by the same coherent receiver. Simulation results based on realistic system parameters show that both deterministic classical communication with a bit error rate of 10^{-9} and secure key distribution can be achieved over 30km single mode fibers. It is conceivable that in the future coherent optical communication network, QKD is operated in the background of classical communication at negligible cost.