Exploitation of Genuine Time-Bin Entanglement for Quantum Networks

The generation of entanglement between remote nodes is a fundamental requirement for quantum networks, enabling applications such as distributed quantum computation, quantum key distribution, and distributed quantum sensing. Although recent years have seen significant advances, deploying dedicated quantum networks remains challenging and expensive, motivating the development of scalable quantum communication systems compatible with existing optical fiber infrastructure. Time-bin entanglement is well-suited to this task because of its robustness against decoherence in optical fibers. Recent works have demonstrated postselection-free schemes for genuine time-bin entanglement. This thesis presents a highly scalable quantum communication architecture based on fast, phase-stable, Sagnac-based optical switches and demonstrates novel experimental schemes for the generation and measurement of time-bin states. An arbitrary quantum state encoder that prepares fully controllable time-bin states is developed and characterized for key applications in quantum key distribution and entanglement generation. An experimental testbed is implemented to distribute entanglement between spacelike-separated measurement stations equipped with quantum random number generators, enabling a Bell test free of the postselection, locality, and freedom-of-choice loopholes. Finally, a universal time-bin receiver is introduced, capable of measuring arbitrary time-bin states and enabling complete characterization of time-bin qubits. Overall, this thesis contributes to advancing the scalability and flexibility of time-bin entanglement, laying the groundwork for future quantum networks leveraging telecom infrastructure.