Quantum teleportation allows quantum information contained in a quantum bit (cubit) to be sent without the need to physically send the cubit. It would therefore be a key element in a future quantum information and communications network. Teleportation can be done with the same photons that circulate in our conventional data networks, so it would be desirable to be able to use existing ones, without the need for new telecommunications infrastructures. However, very large conventional data traffic can affect the more fragile and subtle quantum states.  

In this experiment by researchers at Northwestern University, quantum teleportation is achieved over a 30 km network of conventional fibre optics, carrying 400 gigabits per second of traffic at the same time. Quantum transmission is not perfect, as there is a difference of about 10 % between the information transmitted and received. However, this difference is very similar to that of a teleportation in which a 30 km network with traffic is not used. The researchers therefore show that, in principle, a future quantum communications network could use the same basic fibre infrastructure already in place, as its use does not seem to increase errors significantly. 

But, on the other hand, the 10 % error rate that still appears in basic teleportation experiments shows that we are still in the early stages of a quantum network.