Quantum Communication with Ultrafast Time-Bin Qubits

The photonic temporal degree of freedom is one of the most promising platforms for quantum communication over fiber networks and free-space channels. In particular, time-bin states of photons are robust to environmental disturbances, support high-rate communication, and can be used in high-dimensional schemes. However, the detection of photonic time-bin states remains a challenging task, particularly for the case of photons that are in a superposition of different time bins. Here, we experimentally demonstrate the feasibility of picosecond time-bin states of light, known as ultrafast time bins, for applications in quantum communications. With the ability to measure time-bin superpositions with excellent phase stability, we enable the use of temporal states in efficient quantum key distribution protocols such as the BB84 protocol.

Automated summary

The photonic temporal degree of freedom is a promising platform for quantum communication. Despite the challenges in detecting photonic time-bin states, the feasibility of picosecond time-bin states for quantum communication has been experimentally demonstrated.