Abstract

In the context of quantum information technologies superconducting qubits (SQs) are very promising devices for the quantum manipulation of states, and have attracted a lot of attention in the later years. However, SQs couple naturally to microwave frequencies, which presents a challenge for their integration into larger scale quantum systems. The reasons for that are the lack of a quantum storage device for microwaves, and the lack of a suitable propagation channel for quantum information at this frequency band. A solution around this problem is to use a so called Quantum Frequency Converter (QFC): a device capable of changing the frequency of a single photon at a time, while maintaining its quantum properties intact. The requirements for such a conversion process are that it must be coherent, efficient and noise-free. If the microwave output photons of SQs could be converted to the optical or the telecommunications band in this way they could then be coupled into optical fibres, which are the best suited channels for quantum communications at the present time.

© 2015 IEEE