Developing Practical Quantum Network Protocols*

We outline a vision for developing the Quantum Internet Protocol and describe our experiences with implementing a protocol prototype that allows transmission and synchronization of time-bin encoded photons. Ideally, quantum network protocols should satisfy a long list of requirements, including the ability to transmit heterogeneous types of quantum and classical information; ensure precise timing; scale with the number of users and applications; and allow upgradability. We work towards these goals by introducing a new protocol that allows transmission of DV, CV, and hybrid entanglement and uses in-band transmission of classical control signals. We also report on our development and experimental demonstration of a protocol prototype that uses FPGAs to control the transmission and synchronization of time-bin encoded photons between a pair of network nodes separated by 20 km of optical fiber [1]. Our technique achieved timing synchronization with picosecond accuracy and required only a single dedicated optical fiber and standard internet connection between the two network nodes. The accurate timing information allowed us to use time-bin encoding and increase data transmission speeds.