Abstract This thesis, developed during an experimental research project at the Italian Na- tional Metrology Research Institute (INRIM) in Turin, focuses on the practical implementation of the Twin-Field Quantum Key Distribution (TF-QKD) protocol. This approach is promising for realizing quantum-secure communication over long distances, as it suffers less from transmission loss compared to more conventional QKD protocols. However, it requires ultrastable lasers and fully coherent photon propagation over noisy channels. The main objective of my research was to address the key technical challenges that have so far impeded its long-distance application in real-world optical fiber networks, with a particular focus on maintaining phase coherence.