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.
@article{arxiv.2106.09833,
title = {Quantum communication with ultrafast time-bin qubits},
author = {Frédéric Bouchard and Duncan England and Philip J. Bustard and Khabat Heshami and Benjamin Sussman},
journal= {arXiv preprint arXiv:2106.09833},
year = {2021}
}